Talk:Book - An Introduction to the Study of Embryology

Digitized by the Internet Archive in 2017 with funding from University of Toronto https://archive.org/details/introductiontostOOhadd

AN

INTRODUCTION

TO THE

STUDY OF EMBRYOLOGY.

BY

ALFRED C. HADDON, M.A. (Cantab.), M.R.I.A.

PROFESSOR OF ZOOLOGY IN THE ROYAL COLLEGE OF SCIENCE, DUBLIN.

With gtumnwtf gltetration#.

PHILADELPHIA :

P. BLAKISTON, SON & CO.,

1012 WALNUT STREET.

1887.

TO

IT b c /!!> c m o v p

OF

HIS BELOVED MASTER AND FRIEND,

FRANCIS MAITLAND BALFOUR,

This Book

IS DEDICATED

BY

THE AUTHOR.

Protective Structures. - Invertebrates. - Exoskeleton of Arthropoda, p. 98. Skeletal structures of Coelenterata, p. 98. Hematocysts, p. 99. Shells of Mollusca, shell gland, pp. 99, ioo. Chordata. - Skin of Chordata, pp. 1 00-102. Epitrichial layer, p. ioo. Nails, claws, hairs, &c., p. 102. Down-feathers, contour-feathers, pp. 102, 103. Scales, teeth, pp. 103-105.

Epiblastic Glands. - Unicellular and multicellular glands, evolution of complex glands, pp. 105, 106. Mammary glands, 106, 107. Provisional renal organs of Molluscan Yeliger, p. 108.

Muscular Elements. - Ectodermal muscles of Ccelenterates and epidermal muscle-fibres of sweat-glands, p. 108.

Respiratory Organs. - Invertebrates. - Gills of Lamellibranchs, &c., p. 108. Anal respiration in Arthropods; aerial respiration of Mollusca and Arthropods, p. 109. Chordata. - External gills of Fishes and Amphibia, p. 109. Accessory respiratory organs of Teleosts, p. 109.

Stomodamm. - Nature of stomodaeum, oral organs, p. no.

Pituitary Body. - Development of hypophysis in the Lamprey, Frog, and Teleostei, pp. no, in.

Proctodaeum. - Origin of proctodseum, p. in. Malpighian tubules of Tracheates, p. in. Cloaca of Vertebrates, p. 112.

Nervous System of Invertebrates. - Diffused nervous system of Coelenterates, Echinoderms, some Nemerteans, pp. 112, 113. Development of nervous system in Oligochaetes, Molluscs, and Arthropods, pp. n 3-1 15. Nature of the Invertebrate brain, pp. 115, 116.

Central Nervous System of the Chordata. - Neural plate, groove, and canal, p. 116. Neurenteric canal, pp. 116, 117. Neural pore, p. 117. Solid neural keel, p. 118.

Spinal Nerves. - Origin and main branches of spinal nerves, pp. 119, 120. Neural crest, p. 120. Sympathetic nervous system, p. 120.

Histogenesis of the Spinal Cord, pp. 121, 122.

Development of Vertebrate Brain. - The primary brain vesicles, pp. 122, 123. Description of the brain of the adult Frog, and comparison with embryo Fowl, pp. 1 23-1 25. Posterior Brain Vesicle: medulla, fourth ventricle, cerebellum, pons, pp. 125, 126. Middle Brain Vesicle : mesencephalon, optic lobes, iter, crura, pp. 126, 127. Anterior Brain Vesicle: thalamencephalon, infundibulum, chiasma, optic thalami, pp. 127, 128. Pineal gland, epiphysial eye, pp. 128, 129.

Cerebral hemispheres, pp. 129, 130. Corpus striatum, hippocampus, p. 131. Septum lucidum, fornix, corpus callosum, p. 132. Cerebral convolutions, p. 133. Olfactory lobes, p. 133. Summary of History of Mammalian Brain, p. 134.

Cranial Nerves. - Mode of origin and general distribution, commencing from behind forwards, pp. 134-13 7. Hypotheses respecting the segmental value of the cranial nerves, pp. 13 7-1 39.

Serial Cranial Sense Organs, p. 139. Thymus gland, p. 139. Segmentation of the Head, secondary and probably independent of the metamerism of the body, pp. 140, 141.

Sense Organs. - Tactile Organs, p. 141. Olfactory Organs.

- Osphradia of Mollusca, p. 142. Vertebrate nose,

nasal groove, posterior nares, pp. 143-145. Gustatory Organs, p. 145. Auditory Organs. - Invertebrates. -

Various forms of auditory organ in Medusae, pp. 145, 146. Otocysts of Mollusca, p. 146. Auditory organs of Arthropods, p. 147. Chordata. - Otocysts of Tunicates, pp. 147, 148. The Organs of the Lateral Line, p. 148. The Vertebrate Ear. - Auditory sac, semicircular canals, cochlea, scalae, pp. 148-150. Accessory auditory apparatus of Fishes, p. 150 ; of air-breathers, Eustachian tube, external auditory meatus, tympanum, auditory ossicles, pp. 15 1, 152. Visual Organs. - General considerations, pp. 152, 153. Eyes of Invertebrates. - Inverted eyes of Pecten and Onchidium, p. 152. Arthropod eye, pp. 153, 154. Evolution of Molluscan eye, pp. 154-15 7. Eyes of Vertebrates. - Primary optic vesicle, optic cup, lens, cornea, retina, optic nerve, pp. 157-161. Humours, eyelids, p. 162. Epiphysial eye, pp. 162, 163. Hypothetical evolution of the Vertebrate eye, pp. 163, 164.

Observations on the Evolution of the Nervous System and Sense Organs, p. 164. - Diffused ecto- and endodermal nervous system of Actiniae; mesenchymatous nervous system of Lineus ; development of nervous system of Mollusca ; nerve and sense cells of Sponges ; possibility of origin of nervous tracts from mesodermal tissue, p. 165. Evolution of sense and nerve cells, p. 166. Diffused nervous system in Balanoglossus, and deeper (nervous) layer of the epiblast in certain Vertebrate embryos, p. 167.

CHAPTER VI.

Organs Derived from the Hypoblast . . . 1 68-188

Digestive Organs of Invertebrates. - Mesenteron of Acoelomata and of Coelomata, pp. 168-170. The â€œliver- of Invertebrates, pp. 170, 171.

Mesenteron of Chordata. - Formation of mesenteron in telolecithal ova, pp. 171, 172. Pharynx and endostyle ; oesophagus, p. 172. Stomach, liver, and gall-bladder, p. 173. Pancreas, p. 174. Intestine, pp. 174, 176.

Spiral valve, pyloric cseca, p. 175. Caecum, p. 176.

Endodermal Muscles. - Endodermal muscles in Coelenterata, p. 176.

Respiratory Organs. - Intestinal respiration of Invertebrates, p. 177. Pharynx of Chordata; Balanoglossus, p. 177. Tunicates, Amphioxus, p. 178. Ichthyopsida ; branchial chamber, pp. 178, 179. Intestinal respiration in Teleosts, p. 180. Air-bladder, its hydrostatic, respiratory, and auditory functions, pp. 180, 18 1. Lungs, pp.

181, 182.

Tongue. - Development of tongue from pharynx ; taste bulbs, pp. 182, 183.

Thyroid Body and Thymus Gland, pp. 183-185.

Gustatory Organ of Amphioxus, p. 185.

Excretory Organs. - Urinary tubes of Amphipods, p. 186.

Skeletal Structures. - Notochord, Hemicordata, Urochordata, Cephalochordata, p. 186. Vertebrata, pp. 186188. Sub-notochordal rod; significance of the Notochord, p. 188.

Urinary Bladder, p. 188.

CHAPTER VII.

Organs Derived from the Mesoblast . . . 189-264

Indifferent Mesoblast. - The general parenchyma of the body of Sponges, Ccelenterates, and Platyhelminths ; leucocytes, pp. 189, 190.

Dermal Mesoblast. - Derma, p. 190.

Muscular System. - Muscles of Invertebrates and Chordata ; primary segmentation of mesoblastic somites, pp. 1 89, 1 9 1.

Dermal Skeletal Structures. - Invertebrates, p. 192. - Chordata. - Dermal scales of Fishes and Reptiles, pp. 192, 193.

Mesodermal Endo-Skeletal Structures. - Invertebrates. -

Spicules, cartilage, pp. 193, 194. Chordata. - Vertebral column, p. 194. Skeletogenous sheath of notochord, pp. 194, 195. Vertebral arches and bodies in Fishes, pp. 195-197* Amphibia, pp. 197, 198. Sauropsida and Mammals, pp. 198, 199^ Evolution of the vertebral column, p. 199. Ribs, pp. 199, 200. Sternum, p. 200. Pectoral girdle, pp. 200-202. Pelvic girdle, p. 202. Locomotory appendages of Invertebrates, p. 202 ; and Chordata - median fin, p. 203 ; caudal fin, pp. 203, 204; paired limbs, p. 204. Skull - cranium, pp. 205-207 ; visceral arches, pp. 207, 208; mandibular arch, p. 209 ; hyoid arch, pp. 209, 210 ; branchial arches, p. 210; dermal bones, p. 210.

Body-Cavity. - Formation of coelom in Invertebrates and Chordata, pp. 211, 212. Mesentery, p. 212. Pericardium, diaphragm, pleurae, p. 213. Abdominal pores, pp. 213, 214.

Vascular System. - Development of blood-vessels, pp. 214, 215. Formation of the Heart in Invertebrates, pp. 215,216; and V ertebrates, pp. 2 1 7-2 2 3 ; cardiac flexure, p. 219; differentiation into chambers, pp. 220-222; position of the great blood-vessels, pp. 222, 223. Development of the Vascular System in Vertebrates, p. 223. (1.) Early stages of embryonic circulation, pp.

224, 225. (2.) Vitelline circulation, p. 226. (3.) Later

stages of foetal circulation, pp. 226-229. Renal portal system, p. 229. Hepatic portal system, pp. 229-230. (4.) Allantoic circulation, pp. 230-232. Circulation in Ichthyopsida, pp. 232-235. Summary of the history of the aortic arches, p. 235. Changes undergone in the circulation of foetal Mammals, pp. 235-237.

Excretory Organs. - Plan of structure of nephridia, p. 237. Invertebrates, pp. 237-239. Chordata. - Pronephros head-kidney of larval Ichthyopsida and Fowl, pp. 239-241. Mesonephros, Wolffian body of' adult Ichthyopsida and embryonic Amniota, pp. 241-246. Metanephros, pp. 246, 247. Summary of the development of the Vertebrate excretory organs, pp. 248, 249. Epiblastic origin of the segmental duct, pp. 249, 250.

Urogenital Ducts of Vertebrates. - Segmental or archinephric duct, p. 251. Mullerian duct or oviduct, pp. 251,

xvii

XV 111

CONTENTS.

252. Mammalian uterus, pp. 252-254. Recapitulation, p.254. Wolffian or mesonephric duct, p. 254. Testicular network, p. 255. Yas deferens, Gaertner -s duct, pp. 256, 257. Generative ducts of Ganoids and Teleosts, p. 258. Metanephric duct or ureter, pp. 258, 259.

Suprarenal Bodies. - Double origin of suprarenals from degenerate nervous and renal tissue, pp. 258, 259.

Urinary Bladder. - Urinary bladder the. persistent stalk of the allantois, urachus, p. 259. Urogenital sinus and urethra, pp. 259-261. Proctodseum, cloaca, anus perineum, p. 261.

Mammalian External Generative Organs. - Genital eminence and genital folds, pp. 261, 262.

Generative Organs. - Origin of sexual cells in Sponges, Coelenterates, Turbellarians, Sagitta, and the Coelomata, pp. 262-264.

CHAPTER VIII.

General Considerations . . . . . 265-280

Complexity of Embry ological Phenomena. - Advantages of an abbreviated over a phylogenetic development; struggle for existence equally operative upon larvae and adults ; caution against a too ready acceptance of hypotheses professing to explain developmental phenomena, pp. 265-267.

Sketch of a Possible Evolution of Metazoa. - Cell-units and cell-aggregates ; protoplasmic continuity in animals ; specialisation of groups of cells into primary tissues having limited function, pp. 267, 268.

Brief History of Mesoblastic Tissues. - Mesamceboids ; skeletal, vasifactive, and haemolymph tissues ; entoplastic or ectoplastic differentiations of cell-protoplasm ; archenteric diverticula and mesenteries ; evolution of heart and development of blood-vessels ; the excretory organs passed by, pp. 268, 271.

Embryonic Digestion. - The ovum and food-yolk, p. 271.

(1.) Hypoblastic Digestion, p. 272. The occurrence of intracellular digestion in many adult Metazoa, and probably in the embryos of all; the evolution of the digestive glands, p. 273. Gastric education in the newly

CONTENTS.

XIX

bom young of certain animals, p. 273. (2.) Epiblastic

Digestion. - Larval Actiniae ; foetal membranes of Amniota, p. 273. (3.) Mesoblastic Digestion. - Mesamoe boids or phagocytes in Echinoderm larvae devouring effete cells ; their prophylactic function ; the behaviour of leucocytes in Vertebrate digestion, p. 274. Digestion in Sponges, p. 274. Nutritive function of the allantois, pp. 274, 275.

Embryonic Respiration. - Respiration by general surface of the body, p. 275. Respiratory organs - (1) phylogenetic organs utilised in ontogeny ; (2) larval respiratory organs, sui generis. (1.) Gills of larval Elasmobranchs (p. 275) and Frogs, p. 276. (2.) Respiration in Sauropsida and

Prototheria by yolk-sac and allantois, and in Eutheria through maternal blood, p. 276.

Evolution of Nervous System and Sense Organs. - Reference to previous account of the development and differentiation of the nervous system and sense organs, pp. 276, 277.

Continuity of Germ-Producing Tissue. - The nucleus of the germ-cell, supposed by AVeismann to be composed of germ-plasma and histogenetic-plasma, the former alone being essential to reproduction, p. 277. Retention of germ-plasma in those tissues which can reproduce in a vegetative manner, but normally it is almost totally confined to the germ-cells, p. 278. The views of Geddes on growth, pp. 278, 279. Reproduction asexual and sexual, p. 279. Nature of sex, pp. 279, 280. Oogenesis and spermatogenesis, p. 280. Fertilisation, p. 280.

LIST OF ILLUSTRATIONS.

Fig. i Reproduction amongst Protozoa. A-C. Amoeba [after Howes ] ; D. Paramaecium ; E. Stylonycliia ; F. Vorticella [after Stein].

Fig. 2 SPERMATOZOA [from various sources], i. Sponge; 2. Hydroid; 3. Nematode ; 4. Crayfish ; 5. Snail ; 6. Electric Ray ; 7. Salamander ; 8. Horse ; 9. Man.

Fig. 3. Section through a Portion of the Ovary of a Mammal. Illustrating the mode of development of the Graafian follicles. [From Wiedersheim.]

Fig. 4. Diagrams of Ova [from various sources after Geddes]. a. Typical ovum. b. Hydra [after Kleinenberg]. c. Toxopneustes variegatus [after SelenJca]. d. Strongylocentrotus lividus [after Hertwig].

Fig. 5. Ovum OF the Cat. Highly magnified ; semi-diagrammatic. [From Quain after Schafer.]

Fig. 5*. Typical Cell and Nucleus of the Intestinal Epithelium of A Flesh-Maggot (Asticot). Treated with osmic acid vapour. [From Carnoy.]

Fig. 6. A Fowl-s Egg after about Thirty Hours - Incubation. Viewed from above, the upper portion of the shell being removed. [From Kolliker after Von Baer.]

Fig. 7. Formation of Polar Cells in a Star- fish (Asterias glacialis). [From Geddes - A-K. after Fol ; L. after Hertwig.]

Fig. 8. Formation of Polar Cells in Ovum of Elysia viridis.

Fig. 9. Spermatogenesis. A-H. Rat [after H. H. Brown]. I-N. Elasmobranch [after Semper]. O-S. Earthworm [after Blomfield].

Fig. 10. Fertilisation of Ovum of Star-fish (Asterias glacialis). [From Geddes after Fol.]

Fig. 11. Fertilisation of Ovum of Elysia viridis.

Fig. 12. Early Stages of Segmentation of Elysia viridis. Drawn from the living egg.

Fig. 13. Nuclear Division. A-H. Karyokinesis of a tissue-cell. d-f. Karyokinesis of an egg-cell. [Chiefly modified from Flemming.] X, Z. Direct nuclear division in the cells of the embryonic integument of the European Scorpion. [After Blochm arm.]

Fig. 14. Early Stages of Segmentation of Elysia viridis. Drawn from the living egg.

Fig. 15. Segmentation of Oosperm of Frog. [From Balfour after Ecker.]

Fig. 16. Gastrulation of Echinus. [A-C original ; D and E. from living embryos after Metschnikojf.]

Fig. 17. Gastrulation of Fiona nobilis.

Fig. 18. Segmentation of Two Prosobranchs : to illustrate the effect of the increase of food-yolk. A.-D. Ianthina. [a-g. Fusus after Bobretzky.]

Fig. 19. Syncytial Segmentation of Peripatus. [After Sedgwick.']

Fig. 20. Segmentation of Oosperm of Callianassa subterranea. [After Mereschkowski. ]

Fig. 21. Blastula and Gastrula of Fresh- water Crayfish (Astacus fluviatilis). [After Reichenbach and Huxley.]

Fig. 22. Figures Illustrating the Development of the Archenteron and Origin of Mesoblast of Astacus. [From T. J. Parker after Reichenbach.]

Fig. 23. Blastula and Gastrula of Amphioxus. [From Claus after Hatschek.]

Fig. 24. Blastula and Gastrula Stages of the Frog (Rana temporaria)

[After Gotte.]

Fig. 25. Three Diagrammatic Longitudinal Sections through an Ideal Type of Vertebrate Embryo, Intermediate in the Mode of Formation of its Layers between Amphibia or Lamprey and Elasmobranchii. [From Balfour.]

Fig. 26. Longitudinal Section through the Blastoderm of an Elasmobranch during Gastrulation. [Modified from Balfour.]

Fig. 27. Surface Views of Six Stages in the Segmentation of a Fowl -s Oosperm. [From Kblliker after Coste.]

Fig. 28. Semi-Diagrammatic Section through a Fowl -s Blastoderm corresponding to No. 3, Fig. 27. [Modified from Kblliker (A) and Balfour , B, C.]

Fig. 29. Section through the Blastoderm of an Unfertilised newlylaid Fowl -s Ovum in the Blastula Stage. [After Duval.]

Fig. 30. Semi-Diagrammatic Section through the Germinal Disc of a Fowl during the Later Stages of Segmentation.

Fig. 31. Portion of a Section through an Unincubated Fowl -s Oosperm. [From Klein. ]

Fig. 32. Section through the Blastoderm of an Unfertilised Canary -s Ovum in the Gastrula Stage. [After Duval.]

Fig. 33. Surface View of the Pellucid Area of the Blastoderm of A Fowl of Twenty Hours. Magnified 24 diameters. [From Kblliker after His.]

Fig. 34. Transverse Section through the Anterior End of the Primitive Streak of a Fowl -s Blastoderm about the Age of Fig. 34. [From Balfour. ]

Fig. 35. Diagrams Illustrating the Position of the Blastopore, and the Relation of the Embryo to the Yolk in Various Meroblastic Vertebrate Oosperms. [From Balfour .] A. Type of Frog. B. Elasmobranch type. 0 . Amniotic Vertebrate.

Fig. 36. Portion of the Blastoderm of an Abnormal Fowl -s Ovum of Eighteen Hours - Incubation. [After Whitman .]

Fig. 37. Section through the Yolk-Blastopore of Oosperm of Nightingale. [A fter Duval. ]

Fig. 38. First Stages of Segmentation of a Rabbit -s Oosperm : SemiDiagrammatic. [From Quain; drawn by Allen Thomson after E. Van Beneden' s description.]

Fig. 39. Sections through the Oosperm of the Rabbit during the Later Stages of Segmentation, showing the Formation of the Blastodermic Vesicle. [From Quain after E. Van Beneden. ]

Fig. 40. Section through the Blastodermic Vesicle of a Bat. [After Van Beneden and Julin.]

Fig. 41. Diagrammatic Section of a Mammalian Blastodermic Vesicle, in which the Primitive Invagination of the Blastoderm is Rectified, and the Covering Cells have Extended over the Blastoderm.

Fig. 42. Rabbit -s Oosperm Seven Days after Impregnation. 3.47 mm. in length. Side view deprived of its envelopes. Magnified about 10 diameters. [From Kolliker .]

Fig. 43. Sections through the Blastoderm of a Mole (Talpa) [After Heape .]

Fig. 44. Diagrammatic Transverse Section through the Blastoderm and Yolk of the Oosperm of a Hypothetical Primitive Mammal.

Fig. 45. Diagrammatic Transverse Sections through a Hypothetical Mammalian Oosperm.

Fig. 46. Formation of the Planula of Obelia. [After Merejkowsky.]

Fig. 47. Sections through Three Stages in the Segmentation of Geryonia. [After Fol.]

Fig. 48. Blastula of Echinus. Drawn from the living embryo. [After Metschnikoff.)

Fig. 49. Origin of Mesenchyme in Lineus. [After Hubrecht .]

Fig. 50. Gastrulation and Origin of Mesoblast in Leptoplana Tremellaris. [A fter Hallez.]

Fig. 51. Four Stages in the Development of Argiope. [After Kowalevsky.]

Fig. 52. Three Larval Stages of the Star-fish (Asterias).

Fig. 53. Gastrulation and Formation of Mesoblast in Rhynchelmis (E uaxes). [After Kowalevsky.]

Fig. 54. Origin of the Mesoblast in Astacus. [From T. J. Parker after Reichenbach.]

Fig. 55. Diagrammatic Representation of an Ideal Gastrula Stage of an Insect at the Time when the Archenteric Diverticula are Formed. [After 0 . and E. Hertwig .]

Fig. 56. Transverse Sections of Embryos of Amphioxus. [ After Hatschek.]

Fig. 57. Three Larval Stages of Amphioxus. [From Claus after Hatschek.]

Fig. 58. Late Gastrula Stage of the Newt (Triton). [After 0 . Hertwig.]

Fig. 59. Transverse Section of the Dorsal Portion of an Embryo Newt (Triton). [After 0 . Hertwig .]

Fig. 60. Late Gastrula Stage of Lamprey. [After Scott]

Fig. 61. Transverse Sections through the Upper Portions of Two Embryo Lampreys (Petromyzon planeri). [After Calberla .] A. Same stage as Fig. 63. B. Later stage.

Fig. 62. Gastrula and Formation of Mesoblast of the Frog. [After 0 . Hertwig .]

Fig. 63. Origin of Mesoblast in a Fresh-water Turtle (Trionyx). [After Mitsukuri and Ishikawa.]

Fig. 64. Transverse Section through a Portion of the Blastoderm OF A Lizard (Lacerta Muralis). [After Weldon .]

Fig. 65. Transverse Section through the Anterior End of the Primitive Streak of a Fowl -s Blastoderm about the Age of Fig. 34. [From Balfour .]

Fig. 66. Section through the Germinal Ridge of a Fowl -s Blastoderm. [ After Kollmann.]

Fig. 67. Sections through the Blastoderm of a Mole (Talpa). [After Heape .]

Fig. 68. Ideal Section through the Long Axis of a Sea- Anemone.

Fig. 69. Embryos of Peripatus Capensis. [After Balfour.]

Fig. 70. Transverse Section of an Embryo Fowl of Three Days - Incubation. The size of the embryo is exaggerated. [From Kolliker.]

Fig. 71. Details of the Edge of the Mesoblast of a Fowl -s Ovum about THE Stage OF Fig. 70. [After Duval.]

Fig. 72. Diagrams Illustrating the Formation of the Amnion and Allantois. [From Bell after Foster and Balfour .]

Fig. 73- Formation of the Allantois. Longitudinal section of the posterior extremity of an embryo Fowl of the third day. Osmic acid preparation strongly contracted by the reagent. Magnified 150. [From Kolliker .]

Fig. 74. A. Diagrammatic Longitudinal Section through the Egg of a Fowl. B. Detail of a Portion of the same at a Time when the Allantois reached the Spot marked x in A. [After Duval.]

Fig. 75. Diagrams Illustrating the Formation of the Placental Sac in Birds (Warbler). [After Duval.]

Fig. 76. Diagrammatic Dorsal View of an Embryo Rabbit with its Membranes at the Stage of Nine Somites. [Modified from Van Beneden and Julin.]

Fig. 77. Diagrammatic Median Vertical Longitudinal Sections through the Embryo Rabbit. [After Van Beneden and Julin .]

Fig. 7S. Fcetal Envelopes of a Rabbit Embryo. [From Minot after Van Beneden and Julin.]

Fig. 79. Five Diagrammatic Figures Illustrating the Formation of the Fcetal Membranes of a Mammal. [From KolliJcer,]

Fig. 80. Diagram of the Fcetal Membranes of the Virginian Opossum. [After Osborn.]

Fig. 81. Diagram of the Fcetal Membranes of the Native Bear.

[After Caldwell.]

Fig. 82. Diagrammatic Longitudinal Section of Ovum of Rabbit at an Advanced Stage of Pregnancy. [From KolliJcer after Bischoff.]

Fig. 83. Diagrammatic Section of Pregnant Human Uterus, with Contained Fcetus. [From Huxley after Lon get.]

Fig. 83*. Diagrams Illustrating the Inversion of the Germinal Layers in the Blastodermic Vesicle of Rodents. A-C. Fieldvole (Arvicola arvalis) [after Kupffer]. D. House-mouse (Mus musculus) [after SelenJca]. E-H. Rat (Mus decumanus) [after Fraser].

Fig. 84. Veliger Larvae of Mollusca. A. Veliger of Purple-snail (Ianthina). B. Early veliger of the Pond-snail (Lymnseus stagnalis). C. Optical section of primitive kidney of embryo Murex. D. Section of shell-gland of the same. [B. only after Howes.]

Fig. 85. Sections of Skin of Embryo Birds. [After Jeffries.]

Fig. 86. Six Stages in the Development of Hair. [From Wiedersheim.]

Fig. 87. Development of Feathers. [After Jeffries.] A-C. Duckling. D. Robin.

Figs. 88, 89. Early Stages in the Development of Milk-Teeth. [From Landois and Stirling.]

Fig. 90. Later Stage in the Development of a Tooth. [From Wiedersheim.]

Fig. 91. Diagrams to Illustrate the Evolution of Complex Glands.

[After Huxley.]

Fig. 92. Diagrams of the Arrangements of} the Ducts of the Mammary Glands in Various Mammals. [From Bell after Klaatsch]

A. Adult Echidna. B. Human embryo. C. Human adult. D. Adult Mouse. E. Embryo Cow. F. Adult Cow.

Fig. 93. Development of Mammary Glands of Marsupials. A. Phalangista vulpina (9.5 cm.) B. Perameles gunii (8.6 cm.) [After Klaatsch.]

Fig. 94. Diagrams to Illustrate the Relation of the Pituitary Invagination TO THE STOMODiEUM. A. Embryo Lamprey [from Scott].

B, C. Embryo, and a young Tadpole, respectively of a Toad (Bombinator) [ from Scott after Gotte].

Fig. 95. Sections to Illustrate the Development of the Nervous System in an Earthworm (Lumbricus trapezoides). [After Kleinenberg.]

Fig. 96. Origin of Nervous System in the Dog-Whelk (Purpura).

Fig. 97. Embryo of Frog, with Slit-like Blastopore and welldeveloped Neural Folds. [After 0 . Hertwig .]

Fig. 98. Diagrammatic Longitudinal Section through the Embryo of A Frog. [From Balfour after Gotte .]

Fig. 99. Longitudinal Section through an Advanced Embryo of a Toad (Bombinator). [From Balfour after Gotte.]

Fig. 100. Embryo Fowl, 3 mm. long, of about twenty-four hours ; seen from above ; magnified 39 diameters. [From Kolliker.]

Fig. 101. Embryo Fowl, 4.2 mm. long, of the second day; seen from above ; magnified a little over 50 diameters. [From Kolliker.]

Fig. 102. Transverse Section through the Trunk of an Embryo DogFish (Pristiurus). [From Balfour.]

Fig. 103. Transverse Section through the Anterior Part of the Trunk of an Embryo Dog-Fish (Scyllium). [From Balfour.]

Fig. 104. Vertical Longitudinal Section through Part of the Trunk of a Young Scyllium Embryo. [From Balfour.]

Fig. 105. Diagrams Illustrating the Formation of the Anterior and Posterior Fissures of the Lumbar Region of the Spinal Cord IN A Pig. [After Barnes.]

Fig. 106. Dorsal View of Anterior Portion of Embryo Fowl at the End of the Second Day, 4.27 mm. long. Magnified 40 diameters. [From Kolliker.]

Fig. 107. Brain of Frog. A. Dorsal view. B. Ventral view. C. Horizontal section. D. Side view [after Howes]. E. Longitudinal section [after Osborn].

Fig. 108. Diagrammatic Outline of a Longitudinal Section through the Brain of a Fowl Embryo of Ten Days. [ From Quain after Mihalkovics.]

Fig. 109. Longitudinal Section of an Adult Human Brain. [From Wiedersheim after Reichert.

Fig. no. Horizontal Section of the Brain of a Rabbit of Ten Days. Magnified 40 diameters. [From Kolliker. ]

Fig. hi. Horizontal Section of Anterior Portion of the Brain of an Embryo Sheep, 15 mm. long. Magnified 5 diameters. [From Kolliker.]

Fig. 1 1 2. Horizontal Section of the Head of an Embryo Sheep, 15 mm. long. Magnified 50 diameters. [From Kolliker.]

Fig. 1 1 3. Lateral View of the Brain of an Embryo Calf of 5 cm.

[From Balfour after Mihalkovics.]

Fig. 1 14. Brain of a Human Embryo of Six Months. Natural size.

[From Kolliker.]

Fig. 1 1 5. Transverse Section of the Brain of an Embryo Sheep, 2.7 cm. long. Magnified 10 diameters. [From Kolliker.]

Fig. 1 16. Longitudinal Vertical Section through the Anterior Part of the Brain of an Embryo Rabbit of 4 cm. [After Mihalkovics.]

Fig. 1 1 7. Diagram Illustrating the General Distribution of the Cranial Nerves. [ Modified from Beard.]

Fig. 1 1 8. Diagrammatic Transverse Section through the Gill-Bearing Region of an Elasmobranch or other Ichthyopsid. [After Beard.]

Fig. 1 19. Sense-Cells of Ccelenterates. A. iEginura myosura [after Hceckel.] B-E. Carmarina hastata ; F-G. Antliea cereus [after 0 . and B. Her twig].

Fig. 120. Sections through Two Stages in the Development of the Olfactory Organ of an Embryo Dog-Fish (Scy Ilium). [After A. M. Marshall.]

Fig. 12 1. Under Surface of Head of Dog-Fish.

Fig. 122. Ventral Views of the Heads of Embryo Fowls. (1) At the end of the fourth day of incubation. (2) At the commencement of the fifth day. [From Kolliker.]

Fig. 123. Auditory Organs of Various Medusa. [After 0 . and B. Hertwig.]

Fig. 124. Two Stages in the Development of the Otocyst in Murex.

Fig. 125. Transverse Section through the Auditory Involutions of an Embryo Fowl of the Second Half of the Second Day. Magnified 84 diameters. [From Kolliker.]

Fig. 126. Early Stages in the Development of the Vertebrate Ear. A-D. Four stages in the development of the labyrinth of a Fowl. [After Beissner.] E. Transverse section through the auditory pit of a Fowl -s embryo of fifty hours. [After Marshall.] F. Transverse section through the head of a foetal Sheep (16 mm. in length) in the region of the hindbrain. [After Bottcher.]

Fig. 127. Transverse Section of Auditory Labyrinth of an Embryo Cow, 8Â£ lines in length. Magnified 30 diameters. [From Kolliker.]

Fig. 128. Diagram of the Auditory Labyrinth : A. of a Fish ; B. of a Bird ; C. of a Mammal. [From Bell after Waldeyer.]

Fig. 129. Section of Eye of Larva of a Water-Beetle (Dytiscus). [From Bell after Grenacher.]

Fig. 130. Ocellus of Larval Insect. [After Patten.]

Fig. 13 1. Sections through the Developing Eyes of Mollusca. A-B. Gasteropod (Murex). C-D. Cephalopod (Loligo). [The latter after Lankester.]

Fig. 132. Diagrams Illustrating Three Stages in the Evolution of Eye of Gasteropods. [A and C. after Fraisse ; B. after Patten.] A. Patella. B. Haliotis. C. Fissurella.

Fig. 133. Three Diagrammatic Sections of the Eyes of Mollusca. [After Grenacher.] A. Nautilus. B. Gasteropod (Limax or Helix). C. Dibranchiate Cephalopod.

Fig. 134. Diagram Representing the Transformation of Epidermal Cells into Sense and Nerve Cells in Mollusca. [After Patten.]

Fig. 135. Horizontal Section through the Head of an Embryo Fowl, Illustrating the Development of the Eye. A. Embryo of fiftyfour hours - incubation. [After Marshall .] The section is oblique ; on one side it passes through the optic stalk. B. Section of about the same age, through another plane. C. Later stage.

Fig. 136. Diagram Illustrating the Position of the Choroidal Fissure.

Fig. 137. Section of the Eye of a Fowl at the Fourth Day. [From Balfour . ]

Fig. 138. Horizontal Section of the Eye of a Rabbit of Eighteen Days. Magnified 30 diameters. [ From Kolliker.]

Fig. 138A. Diagrams Illustrating the Evolution of the Epiphysis (Pineal Gland). [After Spencer.]

Fig. 139. Diagrams Illustrating a Hypothetical Evolution of the Vertebrate Eye.

Fig. 140. Diagrammatic Sections of Embryos of the Cray-Fish (Astacus Fluviatilis). [From Huxley after Reichenbach.]

Fig. 141. Isolated Alimentary Canal of Embryo Dog of Twenty-Five Days. Multiplied 5 diameters. [From Kolliker after Bischoff. ]

Fig. 142. Diagrammatic Longitudinal Section through the Head of A Larval Lamprey (Petromyzon). [From Claus after Balfour.]

Fig. 143. Four Stages in the Development of the Human Alimentary Canal, as seen from the Left Side and Isolated. [After His.]

Fig. 144. Rough Diagrams Illustrating the Change in Relative pOSITION UNDERGONE BY THE DIGESTIVE TRACT IN MAMMALS.

[From Landois and Stirling. ]

Fig. 145. Head of Embryo Rabbit of Ten Days. Magnified 12 diameters.

[From Kolliker. ]

Fig. 146. Diagrams Illustrating the Visceral Arches and Development of the Tongue in the Human Embryo. [After His.]

Fig. 147. Development of the Thymus Gland and Thyroid Body in the Human Embryo. [After His.]

Fig. 148. Transverse Section of the Dorsal Portion of an Embryo Newt (Triton). [After 0 . Hertwig.]

Fig. 149. Formation of Notochord in a Fresh-Water Turtle (T rionyx). [After Mitsukuri and Ishikawa.]

Fig. 150. Transverse Section through the" Trunk of an ElasmoBRANCH EMBRYO (Pristiurus). [From Balfour.]

Fig. 1 5 1. Horizontal Section through the Trunk of an Embryo Fowl.

Fig. 152. Notochord of Lepidosteus. [After Balfour and Parker.]

Fig- * 53 - Diagram Representing the Various Types of Vertebral Columns in Longitudinal Section. [From Gegenbaur.]

Fig. 154. Longitudinal Section through the Vertebral Column of Various Urodeles. [After Wiedersheim.]

Fig. 155. Diagrams of Two Stages in the Development of an Ideal Chondro-Cranium.

Fig. 156. The Chondro-Cranium and Visceral [Skeleton with the Anterior Part of the Vertebral Column of a Dog-Fish (S cyllium canicula). Seen from the right side j the labial cartilages are omitted. [ After A. M. Marshall.]

Fig. 157. Diagrams Illustrating the Formation of the Heart of (A) Invertebrates and (B) Chordata.

Fig. 158. Transverse Section through the Head of a Rabbit of Eight Days Fourteen Hours. [ From Kdlliker .]

Fig. 159. Transverse Section through' the Cardiac Region of an Embryo Fowl of Thirty-Nine Hours. Magnified 61 diameters. [From, Kdlliker.]

Fig. 160. Transverse Section through the Cardiac Region of an Embryo Fowl of Thirty-Nine Hours. Magnified about 95 diameters. [From Kdlliker.]

Fig. 161. Ventral View of Embryo Fowl at the End of the Second Day. 4.27 mm. long ; removed from the blastoderm. [From Kdlliker.]

Fig. 162. Development of the Mammalian Heart. [From Landois and Stirling.]

Fig. 163. Lateral View of Heart of Human Embryo, the Right Side BEING CUT AWAY. [After His.]

Fig. 164. Diagrammatic Outlines of the Early Arterial System of a Mammal Vertebrate Embryo. [After Allen Thomson.]

Fig. 165. Diagram of the Embryonic Vascular System. [From Wiedersheim.]

Fig. 166. Diagram of the Circulation of the Yolk-Sac of the Fowl at the End of the Third Day of Incubation. [From Foster and Balfour. ]

Fig. 167. Diagrams of the Aortic Arches of a Mammal. [From Landois and Stirling after Rathke.]

Fig. 168. Diagram Illustrating the Transformations of the Aortic Arches in a Lizard, A ; a Snake, B ; a Bird, C ; a Mammal, D. Seen from below. [From Mivart after Rathke. ]\

Fig. 169. Diagram of Three Stages in the Development of the Venous Circulation of the Fowl. [After Balfour.]

Fig. 170. Diagram of the Arrangement of the Principal Vessels in a Human Foetus. [From Claus after Ecker.]

Fig. 1 7 1. Diagrams Illustrating the Development of the Great Veins in Mammals. [From Quain after Kdlliker.]

Fig. 172. Venous Circulation in Mammalian Embryo. [From Landois and Stirling.]

Fig. 173. Pronephros of Ichthyopsida. A. Bombinator [after Gotte J; C. Trout [after Balfour] ; D. Lepidosteus [after Balfour and Parker],

Fig. 174. Diagrams Illustrating the Development of the Pronephros in the Fowl.

Fig. 175. Transverse Section through the Trunk of a Young Embryo Elasmobranch (Scyllium). [From Balfour .]

Fig. 176. Transverse Section through the Trunk of a Duck Embryo with about Twenty-Four Mesoblastic Somites. [From Balfour .]

Fig. 177. Early Stages in the Development of the Wolffian Body in the Fowl. [After Sedgwick. ]

Fig. 178. Development of Metanephros in the Fowl. [Adapted from Sedgwick .]

Fig. 178*. Transverse Section of Embryo Rabbit. 4 mm. in length ; stage of sixteen somites. [After Flemming . ]

Fig. 179. Various Forms of Mammalian Uteri. A. Ornithorhynchus [after Owen]. B. Didelphys dorsigera [after Brass]. C. Phalangista vulpina [after Brass]. D. Double uterus and vagina ; Human anomaly [after Farre]. E. Lepus cuniculus (Rabbit), uterus duplex [after T. J. Parker]. F. Uterus bicornis. G. Uterus bipartitus. H. Uterus simplex (Human). [F-H. after Wiedersheim.]

Fig. 180. Diagram of the Urogenital Apparatus of a Male and Female Urodele. Founded on Triton taeniatus. [From Wiedersheim after J. W. Spengel.]

Fig. 181. Generative Organs of Human Adult. [After Kobelt.]

Fig. 182. Urogenital Organs of a Female Human Fcetus of 3^ Inches Long, or about Fourteen Weeks. [From Quain after Waldeyer.]

Fig. 183. Diagrams Representing the Relations of the Urogenital Organs in the Male and Female Eutheria. [From Landois and Stirling. ]

Fig. 184. Diagram of the Mammalian Type of Male Sexual Organs.

[From Quain.]

Fig. 185. Diagram of the Mammalian Type of Female Sexual Organs.

[From Quain.]

Figs. 186-189. Diagrams Illustrating the Evolution of the Posterior Passages. [From Landois and Stirling.]

Fig. 190. Development of the External Sexual Organs in the Human Male and Female from the Undifferentiated Condition. [After Ecker.]

Appendix

C. Kupffer, - â€œDas Ei von Arvicola arvalis tmd die vermeintliclie Umkehr der Keimblatter an demselbem,- Sitz. d. Math.-Phys. Cl. 7 c. b. AJcad. d. Wiss. z. Milnchen , v. 1882.

U. Lieberkuhn. - â€œ Ueber die Cborda bei Saugethieren,- Arch. f. Anat. u. Phys ., Anat. Abtheil ., 1882-84.

S. Lothringer. - â€œ Untersuchungen an der Hypophyse einiger Saugethiere und des Menschen,- Arch. f. miter. Anat., xxviii. 1886.

K. Mitsukuri.- - â€œOn the Development of the Suprarenal Bodies in Mammalia,- Quart. Jour. Micr. Sci ., xxii. 1882.

W. K. Parker. - â€œ On the Structure and Development of the Skull in the Pig (Sus scrota),- Phil. Trans., 1874.

â€œ On the Structure and Development of the Skull in the Mammalia.- Part ii. , â€œEdentata;- Part iii., â€œ Insectivora - (with Bibliography), Ibid.. 1885.

G. Pouchet et L. Chabry. - â€œ Contribution a TOdontologie des Mammiferes,- Jour. Anat. et de Physiol ., xx. 1884, p. 149.

G. Rein. - â€œUntersuchungen iiber die embryonale Entwicklungsgeschichte der Milchdriise I.,- Arch. f. miter . Anat., xx. 1882.

R. Rubattel. - â€œRecherches sur le Developpement du Cristallin chez rHomme et quelques Animaux sup^rieurs,- Pec. Zool. Suisse, ii. 1885.

W. Salensky. - â€œBeitrage zur Entwicklungsgeschichte der Knorpeligen Gehorknochelchen bei Saugetbieren,- Morph. Jahrb., vi. 1880.

E. Selenka. - Studien iiber Entwicklungsgeschichte der Thiere. I. Keimbldtter und Primitive Organe der Maus. Wiesbaden, 1883. III. Die Bldtterumteehrung im Ei der Nagethiere. Wiesbaden, 1884.

G. E. Spee. - 11 Beitrag zur Entwickelungsgesehichte der friiheren Stadien des Meerschweinchens bis zur Vollendung der Keimblase,- Arch, f. Anat. u. Phys., Anat. Abtheil., 1883.

â€œ Ueber directe Betheiligung des Ektoderms an der Bildung der

Urnierenanlage des Meerschweinchens,- Arch. f. Anat. u. Phys., Anat. Abtheil., 1884, p. 89 (full Bibliography).

K. Strahl. - â€œ Zur Bildung der Cloake des Kaninchenembryo,- Arch, f. Anat. u. Phys., Anat. Abtheil., 1886.

INDEX

Abdominal cavity, 213.

pores, 213, 214, 258.

ling, 262.

splints or â€œribs,- 193, 200.

Abducens, 140.

Abneural blood-vessel, 215.

mesentery, 215.

Abomasus, 173.

Acantkias, pineal gland, 1 29; thyroid body, 184.

Achromatin, 17.

Acraspeda, auditory organ, 145.

Actiniae, ectodermal muscle fibres, ic8 ; ectodermal and endodermal nervous system, 165 ; endodermal muscles, 176; reproduction, 278.

Actinozoa, stomodaeum, 71 ; arcbenteric diverticula, 72 ; mesenteries, 72 ; digestion, 72, 168 ; endodermal respiration, 177 ; connective tissue cells, 189 ; ectodermal digestion in larvae, 273. See â€œActiniae,- â€œ Hexacoralla,- â€œ Octocoralla. -

Adhesive glands, 106. iEginura, sense cells, 1 42. iEquorea, auditory organ, 146. After-birth, 92.

After-brain, 134.

Air-bladder, 180; homology of, 182;

blood supply, 182, 233-235.

Air-sacs of birds, 182 ; of gymnodontes, 182.

Alcyonaria, spicules, 98.

Alecithal ovum, 8 ; segmentation, 16, 17, 20, 21, 29.

gastrulation, 21-23, 3Â° Alisphenoid cartilage, 207.

Allantoic arteries, 224, 231, 232, 237.

vein, 229-233, 236, 237.

Allantois, 81 ; of birds, 81-84; Â°f reptiles, 84 ; of mammals, 87-97 5 evolution, 87, 276; circulation in, 230-232, 234

Alveoli of glands, 105, 173.

Alytes, larval respiration, 87.

Amblystoma, vertebral column, 197.

Ambulacral system, 55, 56.

Amia, scales, 193 ; intercalary arches, 196 ; blood supply of air-bladder, 233, 235 ; oviduct, 258.

Ammocoete. See â€œ Lamprey.- Rudiments of pelvic fins, 204 ; diaphragm, 213.

Amnion, 79 ; of fowl, 79 ; amnion proper and false amnion, 8 1 ; of reptiles, 84 ; of the rabbit, 85 ; mammals, 8797, 231 ; insects, 96.

Amniota, primitive streak, 39, 41, 42 ; embryonic appendages, 78 ; urinary bladder, 78 ; allantoic respiration, 88, 276; cloaca and derivatives, 1 12; neurenteric canal, 117 ; pharynx, 172 ; absence of gills, 1 77 ; thyroid body, 184 ; thymus gland, 185 ; derma, 190 ; muscles, 19 1 ; ribs, 199 ; clavicles, 202 ; cheiropterygium, 204 ; skull, 207-21 1 ; vascular system, 223-232, 235-237 ; pronephros, 241 ; mesonephros, 242 ; vasa efferentia, 256 ; embryonic respiration, 276. See also â€œ Reptilia,- â€œAves,- and â€œ Mammalia.-

Amoeba, reproduction, 3 ; mode of feeding, 7, 272 ; nuclear division, 20.

Amphibia. See also â€œ Frog.- Fate of blastopore, 77, 1 1 7 ; urocyst, 87, 230, 234, 259 ; larval respiratory organs, 87, 276 ; epiblast, 100, 16 6 ; horny teeth of larvae, 105 ; epiblastic respiration and external gills, 109 ; post-anal gut, 117; nervous system, 116-118; cranial flexure, 123 ; corpus callosum, 124, 132; anterior commissure, 124; cerebellum, 126; supra-commissura, 128; pineal gland, 1 1 7, 129 ; posterior commissure, 129 ; fenestra ovalis, 150; columella auris, 151, 152; eyelids,

314

INDEX.

162 ; epiphysial eye, 163 ; relation of epiblast to nervous system, 166, 167 ; pharynx, 172 ; liver, 173 ; Eustachian recess, 179 ; visceral clefts, 179 ; lungs, 181, 182; gustatory cells, 182 ; suprapericardial bodies, 1 84 ; thyroid body,

184 ; thymus gland, 185; muscles, 191; dermal exo-skeleton, 193 ; vertebral column, 196-198; ribs, 199, 200; sternum, 200 ; pectoral girdle, 20 1 ; median fin, 203 ; tail, 203 ; paired limbs, 204 ; mandibular arch, 209 ; hyoid, 210; position of kidneys, 212 ; pleuro-peritoneal cavity, 21 3 ; absence of abdominal pores, 214; heart, 218, 220, 221 ; aortic arches, 227, 233, 235 ; venous system, 234, 235 ; anterior abdominal vein, 230, 234, 235 ; segmental duct, 239, 240, 249, 251 ; pronephros, 239, 240, 241, 252 ; mesonephros, 242, 246, 248; incipient metanephros, 247, 256 ; Mullerian duct (oviduct), 251, 252; rudimentary in male, 254 ; connection between testis and mesonephros, 254-256; ureters, 256.

Amphiblastula, 51.

Amphicoelous vertebrae, 196-198.

Amphineura, nervous system, 115. See â€œ Chiton.-

Amphioxus, segmentation of oosperm, 29, 30 ; mesothelium, 55 ; archenteric diverticula, 59, 60-62 ; mesenchyme, 61 ; mesodermal segmentation, 74 ; liver, 73, 173; epiblast, 100, 166; ciliated neural canal, 116; nervous system, 1 1 7, 119; neural pore, 1 17 ; nerves, 120; unpaired eye, 1 29; gillslits, 135, 178 ; olfactory organ, 142,

185 ; alimentary canal, 1 7 1 ; pharynx, 172; hypopharyngeal ridge, 172; atrium, 178; atrial pore, 178, 214; taste-buds, 182 ; gustatory organ, 185 ; notochord, 186, 188, 194, 205 ; median fin, 203 ; caudal fin, 203 ; body-cavity, 21 1 ; muscles, 19 1, 21 1; blood-vessels, 215, 223, 239; nephridium, 239, 250.

Amphipnous, reduction of gills, 179.

Amphipoda, diverticula of mesenteron, 169, 186, 238.

Amphistylic skull, 209.

Ampullaria, respiration, 109.

Anabas, accessory respiratory organs, 109.

Anableps, development of embryos in ovary, 95.

Anabolism of protoplasm, 278-280.

Anal glands, 1 06.

Anguis, scales of, 103 ; pineal eye, 129. Annelids, otocysts of, 146 ; heart, 215 ; segmental organs, 238. See also â€œ Chsetopoda.-

Annodonta, gills of, 108.

Antelope, placenta, 92.

Antennse of insects, 1 1 5 ; of Crustacea, 1 16.

Antennules, 147.

Anterior abdominal vein, 229-232, 234.

(superior) cardinal veins, 224, 225,

228, 229, 231-234.

commissure, 124, 132, 134.

nares, 144.

primary brain vesicle, 127, 1 34.

(superior) vertebral veins, 228, 229.

Anthea, sense cells, 142.

Anthropoidea, placenta, 92.

Antipathidee, csenenchyma of, 98, 194. Ant- orbital process, 206.

Anura. ^â€œAmphibia,- â€œFrog,- and â€œ Bombinator.-

Anus, 75, hi, 250, 261.

Aorta, 121, 220-222, 224-227.

Aortic arches, 147, 148, 183, 185, 217, 218, 220-227, 2 3 I Â» 233, 235.

Apes, corpus albicans, 127 ; cerebral hemispheres, 130.

Aphides, parthenogenetic reproduction, 279.

Aplysia, shell of, 1 00.

Appendicularia, auditory organ, 147 ; visceral clefts, 177.

Aqueduct of Sylvius, 124, 125. See â€œ Iter.-

Aqueductus vestibuli, 148-150.

Aqueous humour, 162.

Arachnida, spermatozoa of, 3 ; respiration of, 109; Malpighian tubules, 111 ; appendages, 203.

Arbor-vitse, 126.

Archseocytes, 189, 266.

Archenteric diverticula, 55 -69, 73, 270. Archenteron, 23.

Archiccel, 69, 70, 237, 238, 270, 271. Archinephric duct, 239, 249, 25 1. Archinephridium, 249.

Archinephros, 250.

Area opaca, 9, 38, 119, 2 17, 223.

pellucida, 9, 38, 78.

vasculosa, 9, 38, 79, 85, 88, 119,

214, 223, 224, 226.

Areolar epithelium, 106, 107.

Argiope, early development, 55.

INDEX.

315

Armadillo, scutes of, 103, 193; caecum, 176.

Arsenoblast, 14.

Arteria thyreoidea mandibularis, 235.

Arthropoda, segmentation of egg, 27 ; mesoblast, 57, 69; pseudoccel, 69, 70; coelomic cavities, 70 ; segmentation of body, 73 ; head, 74, 75 ; appendages, 75, 202 ; moulting of larvae, 78 ; exoskeleton, 98 ; anal respiration, 109, 275 ; aerial respiration, 109 ; stomodaeum and derivatives, no; proctodaeum, in ; nervous system, 115, 1 16 ; olfactory hairs, 142 ; auditory hairs, 147 ; otocysts, 146, 147 ; acoustic

organ of hexapoda, 147 ; eyes, 153 - 157; mesenteron, 169; â€œliver,- 170; muscles, 191 ; heart, 215 ; excretory organs, 238.

Artiodactyla, placenta, 92.

Arvicola, inversion of blastoderm, 93.

Ascaris, maturation of ovum, 15 ; karyokinesis in, 19.

Ascidians. See â€œ Tunicata.-

Asellus, heart, 216.

Aspidonectes, pharyngeal respiration, 180.

Astacus. See â€œ Crayfish.-

Aster, 10, 18.

Asterias. See â€œ Starfish.-

Atrial, pore of amphioxus, 178, 214.

Atrium of heart, 219, 220, 224.

balanoglossus, 1 77; tunicata, 1 77;

amphioxus, 178.

Auditory epithelium of batrachia, 166.

ganglion, 138.

nerve, 136, 1 38-141.

organ, 139 ; medusae, 145 ; vermes,

146 ; mollusca, 146 ; arthropoda, 146,

147 ; tunicata, 147 ; cerebral auditory organ of tunicata, 148 ; vertebrate, 147-152 ; myxine, 149 ; mesoblastic labyrinth, 150 ; meatus and concha, 15 1; auditory ossicles, 151.

region of cranium, 207.

Aurelia, occasional direct development, 265.

Auricle of heart, 219, 222.

Auricular septum, 221, 222, 237.

Autostylic skull, 209.

Aves. See â€œ Birds.-

Axial nerve of retinophora, 156.

Axillary artery, 226.

Azygos vein, 228, 231-233, 236.

Axolotl, division of leucocytes in, 19 ; retention of gills, 1 79.

Balanoglossus, mesothelium of, 55 ; archenteric diverticula of, 59, 60 ; origin of nervous system, 167 ; pharynx, 172 ; absence of liver, 173 ; respiratory organs, 177; notochord, 186, 188.

Barbs and barbules, 102, 103.

Basi-hyoid and basi-branchial cartilages, 210.

mandibular, 210.

sphenoid cartilage, 207.

Basilar artery, 125.

plate, 206.

Bat, blastodermic vesicle of, 45, 48; proamnion, 86.

Batrachia. See â€œFrog,- auditory epithelium, 166.

Bdellostoma, head-kidney, 259.

Beaks, 102.

Beetle, gastric caeca, 169.

Biconcave vertebrae, 196-198.

Bilateral symmetry, 74, 270.

Birds (Aves), yolk, 6; segmentation, 31, 3^> 37, 38 ; mesoblast, 66, 69 ; festal membranes, 78, 273 ; umbilical cord, 96 ; yolk-sac, 82, 95, 96 ; epidermis of, 101 ; feathers of, 102 ; scutae, 103 ; bursa Fabricii, 112; cerebellum, 126; corpora bigemina, 126; cerebral hemispheres, 129; olfactory lobes, 133 ; auditory labyrinth, 150 ; pineal gland, 163 ; persistence of vitelline duct, 171, 172; crop, 172; liver, 173 ; caeca, 176; air-sacs from lungs, 182 ; thyroid, 184 ; thymus, 185; notochord, 186; muscles, 191 ; sclerotic bones, 193; vertebral column, 198; sternum, 200; pectoral girdle, 201; diaphragm, 213; absence of abdominal pores, 214; heart, 218223 ; division of truncus, 222 ; ventricular septum, 222 ; circulation, 225230 ; mesonephros, 248, 249.

Birgus, respiration, 109.

Bladder, 230, 259 ; veins of, 234.

Blastema, 266 ; Wolffian, 245, 246 ; metanephric, 246-249.

Blastocoel, 21-37.

Blastoderm, 26, 34-48.

Blastodermic vesicle, 44-48.

Blastosphere, 21.

Blastopore, 22 et seq. (â€œBlastopore- of Van Beneden, 44, 48) ; fate of, 75, no, in, 1 16, 250.

Blastula, 21-37, 49, 50, 268, 270.

Blatta, gastric cseca, 169 ; heart, 215.

Blood corpuscles, 214, 2 15-2 17, 267 ; red, white, or colourless, 190. 214.

316

INDEX.

Blood-vessels, origin of, 67, 70, 214, 215.

Body cavity, 61, 68, 72, 78, 21 1, 212.

Bombinator, pituitary body, ill ; neural canal, 1 1 7 ; branchial chamber, 179; segmental duct, 240.

Bovidse, placenta, 92 ; horns of, 102.

Brachio-cephalic vein, 228.

Brachiopoda, mesothelium of, 55, 59; shell, 99 ; nephridia, 237 ; generative ducts, 237, 264.

Brachyura, thoracic ganglion, 116 ; auditory organ, 147.

Brauchise. See â€œRespiratory Organs.-

Branchial arches, 178, 183, 185, 206, 208, 210.

arteries of, 226, 22 7, 233, 235 ; veins,

224.

clefts. See â€œVisceral Clefts.-

sense-organ, 1 37-141.

Branchiostegal membrane, 1 79.

Bronchi, 182.

Buccinum, ova of, 6 ; cannibalism of embryos, 7.

Budding zones, 278.

Bufo, pineal gland, 163 ; branchial chamber, 179.

Bulbus arteriosus, 220, 221, 223, 224.

Bursa Fabricii, 112.

pelvis, 174.

Byssus glands, 106.

Caducibranch amphibia, hyoid, 210.

Csecilia, scutes, 193 ; vertebral column, 197 ; pronephros, 239 ; segmental Wolffian tubules, 248.

Caecum, 176.

Caeliac artery to air-bladder, 182, 233.

Calcispongiae, amphiblastula of, 51.

Calf. See â€œ Cow.-

Callianassa, segmentation, 27, 28.

Calotes, pineal age, 163.

Canalis auricularis, 221.

Canary (Pyrrhula), blastoderm of, 37 ; gastrula of, 32.

Caput epididymis, 260.

Cardinal veins, 224-232, 234.

Carididae, auditory organs, 147.

Carinatae, sternum, 200.

Car marina, sense cells, 142.

Carnivora, placenta, 91 ; nipple of, 106.

Carotid artery, internal, 125, 207, 224, 226, 22 7 ; external, 224, 226, 227.

Carotids, 220, 224, 226, 227, 233, 236.

Carp (Cyprinus), air-bladder, 780.

Cartilage, invertebrates, 194 ; chordata, 1 94-2 10.

Cat (Felis domestica), ovum of, 7 ; Gaertner -s duct, 257.

Caudal artery, 224.

fin, 203, 204.

vein, 228, 229, 231, 234.

Cavia, inversion of blastoderm, 93, 95.

Cell-division, 17, 267.

Centrolecithal ovum, 8, 271 ; segmentation, 27-29.

Cenogeny, 223.

Cephalochordata, notochord of, 186.

Cephalopoda, gastrulation, 24, 26 ; shellsac, 100 ; nervous system, 1 14 ; olfactory pit, 142; eye, 154-156; ink-sac, 1 70; cartilaginous brain-case, 194.

Ceratophrys, dermal bones, 1 93.

Cerebellum, 122-126, 134.

Cerebral hemispheres, 123-125, 127, 128134 Cerianthus, endodermal respiration, 177.

Cervidse, placenta, 92.

Cestracion, mandibular arch, 209.

Cetacea, placenta, 92 ; posterior nares, 144 ; stomach, 173 ; dorsal fin, 203.

Chsetopoda, segmentation, 26 ; mesoblast, 54, 56, 69 ; coelom, 58, 69, 70 ; segmentation of body of, 73 ; otocyst, 146 ; muscles, 19 1 ; parapodia 202 ; setae, 202 ; vascular system, 7Â°> 21 5 ; generative ducts, 237, 264 ; nephridia, 70, 237, 238, 249, 250 ; heart, 270.

Chaetognatha. See â€œ Sagitta.-

Chameleon, pineal gland, 163; branched lungs, 182.

Cheiropterygium, 204.

Chelonia, scales of, 103 ; anal sacs of, 1 12 ; dermal skeleton, 193 ; abdominal pores 214; urinary bladder, 259. See also â€œ Trionyx.-

Chimaera, lateral line, 148 ; pseudo-branch 178; operculum, 179; axial skeleton, 195, 196.

Chiroptera, placenta, 91.

Chiton, nervous system, 114, 115; eyes in shell, 152; larval eyes, 1 52.

Choano -flagellate cells, 168.

Chorda-entoblast, 31, 62, 1 86.

Chorda tympani, 136.

Chordata, segmentation, alecithal, 29, 30 ; effect of increase of yolk, 30-33 ; telolecithal, 33-39 ; origin of mesoblast, 59 69 ; axial hypoblast, 62; coelomic cavities, 70 ; metamerism, 73, 74, 212 ; ancestry, 74 ; fate of blastopore, 7078, no, hi, 250; epiblastic protective structures, 100; epiblastic respiration,

INDEX.

317

109; stomodaeum, no; central nervous system, 116 ; olfactory organ, 143 ; ancestral form, 76, 77, 163, 164; origin of nervous system, 166, 167; mesenteron, 1 7 1 ; pharynx, 172 ; liver, 173 ; intestine 174; branchial region, 177 ; notochord, 186 ; muscular system, 191, 192 ;

dermal skeleton, 192 ; endo-skeleton, 194 ; locomotory appendages, 203 ; paired limbs, 204; body cavity, 21 1 ; formation of blood, 214 ; heart, 219 ; urinary organs, 239, 249.

Chondro-cranium, 205, 207.

Chorion (vitelline membrane), 9 ; (allantoic or true), 87, 90 ; (yolk-sac or false), 90 ; (pseudo-chorion), 95.

Choroid of cephalopoda, 155; of vertebrates, 160-162; pigment layer of, 159-161.

Choroidal fissure, 158-162, 144.

Choroid plexus of fourth ventricle, 1 23126, 134; of third ventricle, 124, 125, 129-134; of lateral ventricles, 130134 .

Chromatin, 8, 18, 277.

Chyle, 274.

Cilia, 98.

Ciliary ganglion, 135, 137-141.

nerve, 138, 139.

Ciliata, nuclear division in, 20.

Ciliated chambers of sponges, 168.

Cirri, 202.

Clavicles, 200-202.

Claws, 102.

Clitoris, 260, 262.

Cloaca of vertebrates, ill; amniota, 1 12 ; opening of segmental duct, 240, 250 ; of ureter, 246 ; of bladder, 259 ; ornithorhynchus, 253 ; prototheria, 257; eutheria, 261.

Clytia, perisarc, 98.

Cobitis, external gills of larva, 109.

Coccygeo-mesenteric vein, 229, 231.

Cochlea, 149, 150.

Cockroach (Blatta), gastric caeca, 169 ; heart, 215.

Coelenterata, mesoderm, 53, 69, 71, 189, 193; radial symmetry, 71; nematocysts, 99 ; unicellular glands, 105 ; ectodermal muscle-fibres, 108; nervous system, 112, 1 14 ; sense-cells, 142; evolution of nervous system, 166 ; gastric diverticula, 168, 270; skeletal structures, 98, 193, 194; origin of sexual cells, 263, 278 ; connection of cells, 267 ; intracellular digestion, 272

See â€œHydrozoa,- â€œ Scyphomedusae,- and â€œ Actinozoa.-

Coelom, 61, 68, 72, 78, 21 1, 212, 213, 2 37, 270.

Coelomata, internal opening of nephridia, 237 ; origin of excretory organs, 249 ; gonads, 263.

Coenenchyma, 98, 193, 194.

Columella auris, 15 1, 152.

Common carotid artery, 227, 231, 235. Common iliac arteries, 224, 232.

veins, 229, 232.

Concha, 151.

Coni vasculosi, 256.

Conjunctiva, nerve supply, 137, 162. Connective tissue, 67, 70, 189, 190. Conus arteriosus, 220, 221.

Convolutions of cerebral hemispheres,

33

Coprodaeum, 112.

Copulatory organs, 112, 260, 262, 264. Coracoid, 201.

Coracoid epiphysis, 201.

Corallium, coenenchyma, 194.

Corium, 103.

Cornea of mollusca, 155, 156; of vertebrates, 153-164.

Corneal cuticula, 156, 1 57.

Cornu ammonis, 130, 131.

Cornua trabeculae, 206.

uteri, 253.

Cornu medium, 184.

Coronary sinus, 228.

vein, 221, 236.

Corpus albicans, 127, 132.

Corpora bigemina, 125-127, 134; quadrigemina, 1 25-1 27, 134.

cavernosa, 260.

Corpus callosum of amphibia and reptiles, 124, 132 ; of mammals, 125, 132 134 striatum, 125, 130-134.

spongiosum urethrae, 260.

uteri, 253.

Costal pleura, 2 1 3.

Costal sternum,

Cow (Bos taurus), nipple of, 107 ; brain of embryo, 130 ; branchial sense organ, 139; auditory labyrinth, 149. Cowper -s gland, 260.

Crab (Cancer), thoracic ganglion, 116 â€¢ auditory organ, 147.

Crangon, eye, 154.

Cranial flexure, 123, 205.

Cranial sense organs, 139, 205.

Cranium, 205-207.

318

INDEX.

Crayfish, spermatozoon of, 4 ; segmentation of, 28, 29 ; mesoblast of, 57, 58 ; stomodgeum and derivatives, 1 10; nervous system, 1 1 5 ; eyes, 153; alimentary canal, 170; heart, 216; direct development, 265.

Crinoidea, nervous system, 1 13; larval skeleton, 194 ; arms, 202.

Criodrilus, nervous system, 1 1 3.

Crista acustica, decapoda (cephalopoda), 146 ; tunicata, 148.

sterni, 200, 201.

Crocodilia, scutes of, 103, 1 93; posterior nares, 144 ; crop, 172 ; abdominal splints, 193, 200 ; vertebral menisci, 198; abdominal pores, 214; ventricular septum, 222.

Crop, arthropoda, no, 169; vertebrates,

172.

Crura cerebri, 125, 127.

Crura of fornix, 132.

Crural veins, 229, 232.

Crustacea, spermatozoa, 3 ; segmentation, 27, 28, 29 ; mesoblast, 57 ; alimentary canal, 76 ; exoskeleton, 98 ; anal respiration, 109, 1 77 ; aerial respiration, 109 ; stomodgeum and derivatives, Iio; proctodgeum, III; nervous system, 115, 1 16 ; auditory

organs, 1 47 ; eyes, 1 5 3, 1 54 ; digestion of yolk, 29, 169 ; mesenteron, 169, 170; digestive cgeca, 169; heart, 216; excretory organs, 238; shell gland, 238 ; suppression of metamorphoses, 265 ; digestion of yolk, 272.

Crypts of Lieberkiihn, 173.

Crystalline cone, 156.

Ctenophora, origin of middle layer, 53, 189.

Cucullanus, gastrulation of, 23.

Cunina, auditory organ, 146.

Cutaneous artery, 235.

Cuticula dentis, 104, 105.

Cuticle, 98, 152-156.

Cutis, 106, 190.

Cuttlefish (Sepia), shell-sac, 100.

Cyclodus, viviparity of, 96 ; scales of, 103 ; pineal gland, 163.

Cyclops, body cavity, 211.

Cyclostomi, fate of blastopore, 1 17 ; post-anal gut, 117 ; cranial flexure, 123; cerebellum, 126; vagus nerve, 135 ; nasal sac, 1 43 ; auditory labyrinth, 149; absence of pancreas, 172; spiral valve, 175 ; gill pouches, 178 ; axial skeleton, 194, 195 ; caudal fin,

203 ; absence -of paired limbs, 204 ; cranium, 207 ; visceral arches, 208 ; basi - mandibular, 210; diaphragm, 213; abdominal pore, 214, 258, 264; intestinal folds, 273. See â€œ Lamprey.-

Cyclothurus, cgecum, 176.

Cyprinoids, accessory auditory apparatus, 150.

Dactylethra, branchial chamber, 179.

Darmentoblast, 31, 62.

Decapoda (cephalopoda), otolith, 146 ;

eye, 155, 156.

(crustacea), gastric mill, 1 10 ; auditory organ, 147; eye, 153, 154; mesenteron, 169, 170; â€œliver,- 170; green gland, 238.

Decidua reflexa, 92.

serotina, 93.

vera, 93.

Deckenschicht, 45, 48.

Delamination, 48-50.

Dentalium, nervous system, 1 14 ; otolith, 146.

Dentine, 104.

Derma, 102, 190.

Dermal, bones of skull, 210.

skeleton, 192, 193, 210.

Diaphragm, 213, 221.

Diaster, 18, 19.

Dibranchiata, eye, 155, 156.

Diencephalon, 134.

Didelphia. See â€œ Metatheria.-

Didelphys. See â€œ Opossum.-

Digestion, 169 ; in actinozoa, 72 ; embryonic digestion, 27 1 ; hypoblastic digestion, 272.

Diphycercal tail, 203.

Diploblastic blastoderm, 86 ; organism, 268.

Diplostichous eye, 153.

Dipnoi, cerebellum, 126; nostrils, 144 ; operculum, 179; air-bladder, 181, 182 ; scales, 193 ; axial skeleton, 194 ; ribs, 199; caudal fin, 203; cranium, 207; mandibular arch, 209 ; abdominal pores, 214 ; circulation in air-bladder, 182, 220; left auricle, 220; septum of conus, 220 ; arterial arches, 233, 23 5 ; blood supply of air-bladder, 233, 235 ; Mullerian duct (oviduct) in male, 254.

Directive bodies (or cells), 10.

Discophora, mesoblast of, 54.

Dispira, 19.

Dog (Canis familiaris), pro-amnion, 86 ; placenta, 91 ; alimentary canal, 1 7 1 .

INDEX.

319

Dog-fish, spinal nerves of, 120, 121 ; olfactory organ, 143, 144; muscles, 1 9 1 ; neural arches, 196; skull, 208. Dog-whelk. See â€œ Purpura.-

Dorsal aorta, 224-228, 233, 235, 236.

blood-vessel, 215,

fin, 203.

mesentery, 2 1 5.

Down feathers, development of, 102. Dragon-flies (Libellulidae), anal respiration in larvae, 109, 275.

Dreissena, gills of, 108.

Duck (Anas), skin of embryo, 100 ; feathers of, 102 ; neurenteric canal, 117 ; mesonephros, 243.

Ductus arteriosus Botalli, 220, 226, 227, 236, 237.

Botalli, 220, 226-228.

Cuvieri, 213, 219, 224, 225, 228 230, 231, 234.

Kollikeri, 146.

thyreoglossus, 184, 185.

venosus, 229-234, 236, 237.

arantii, 23 1.

Duodenum, 175.

Dytiscns, larval eye, 153.

Ear, 148-151 ; epitrichial layer in, 101.

See â€œAuditory Organ.-

Earthworm (Lumbricus), spermatogenesis of, 11, 12 ; gastrulation of, 26; mesoblast of, 56; nervous system, 113 ; typhlosole, 175 ; muscles, 190 ; absence of parapodia, 202.

Echidna, mammary gland of, 107 ; anterior abdominal vein, 232. Echinodermata, segmentation of, 22 ; mesamoeboids of, 53, 69, 189, 274 ; mesothelium of, 55, 56, 60 ; ambulacral system, 55, 177 ; formation of bodv-cavity, 56, 72 ; radial symmetry, 74; nervous system, 1 1 3 ; mesamoeboids devour degenerate tissues, 189, 274 ; spicular skeleton, 22, 189 ; dermal, mesoblast, and calcareous plates, 190 ; muscles, 190; dermal skeleton, 192 ; larval skeleton, 194 ; larval forms, 265 ; phagocytes, 274.

Echinus, 53. See â€œ Sea-Urchin.- Ectoderm, 23.

Ectoplastic tissues, 269.

Ectosarc, 98.

Edentata, placenta, 91, 92.

Edwardsia, endodermal respiration, 177. Efferent ducts of generative organs, invertebrates, 237 ; chordata, 251-261.

Egg-shell, 9.

Eighth cranial nerve, 136, 138-141.

Elasmobranchii, ovum, 5, 8 ; spermatogenesis, II, 12 ; segmentation of egg, 3D 33-35 5 primitive streak, 41, 42 ; nourishment of embryo in uterus, 95, 96, 273 ; placoid scales, 103, 104, 192 ; teeth, 105; external gills, 109, 1 79 ; cerebellum, 126; supra-commissura, 128; pineal gland, 129, 143 ; posterior commissure, 129; olfactory lobes, 133, 143 ; olfactory pit, 143 ; nasal groove, 142-144 ; lateral line, 148, 121 ; auditory organ, 148, 150; tympanum, 150; eyelids, 162 ; pineal gland, 163 ; liver, 173; spiral valve, 175, 234; rectal gland, 176; visceral clefts, 178-179 ; yolk absorbed by external gills, 179 ; oesophageal sac, 181 ; thyroid body, 184 ; supra-pericardial bodies, 184; thymus gland, 184 ; muscles, 19 1 ; shagreen, 192 ; axial skeleton, 195, 196 ; ribs, 199 ; pectoral girdle, 201 ; caudal fin, 203, 204 ; paired limbs, 204 ; cranium, 207, 208 ; visceral arches, 208-210 ; connection of pericardium with coelom, 213; abdominal pores, 214; heart, 218; hyoid aortic arches, 233, 235; vein of spiral valve, 234 ; thyroid and spiracular artery, 235 ; pronephros, 240, 241, 248 ; segmental duct, 241, 249 ; mesonephros, 242, 243, 248, 249 ; secondary tubules, 245, 246 ; incipient metanephros, 247, 256 ; epiblastic origin of segmental duct, 249 ; segmental duct, 251, 252; Mullerian duct, 251, 252; oviduct, 251 ; its anterior orifice, 252 ; Mullerian duct in male, 254 ; connection between testis and mesonephros, 254-256 ; ureters, 256 ; larval respiration, 275.

Elastica limitans externa, 194, 195.

interna, 188, 194, 195.

Elastic fibres, 190.

Electric ray (Torpedo), spermatozoon of, 4.

Elephas, placenta, 91.

Eleventh cranial nerve, 135.

Elysia, polar cells of, 10, 1 1 ; fertilisation of ovum, 13 ; segmentation of, 1 6, 1 7 ; nuclear division, 20.

Embole, 24, 33.

Embyronic membranes. See â€œ Foetal membranes.-

Enamel, 104.

organ, 104, 1 10.

320

INDEX.

Enchylema, 8, 19.

Endoderm, 23.

Endolymph, 149.

Endoskeletal structures, 269 ; invertebrates, 193, chordata, 194.

Endostyle, 172

Endothelium, 69 ; of heart, 216-218,271.

Entoplastic tissues, 269.

Epencephalon, 1 34.

Epiblast, 23 ; organs derived from, 98 ; protective structures, invertebrates, 98 ; chordata, 99 ; teeth, 103 ; glands, 105 ; excretory organs of mollusca, 108, 238 ; muscular elements, 108 ; respiratory organs, 108 ; stomodseum, HO; pituitary body, no; Malpighian tubules, hi, 169, 238; proctodseum, in ; cloaca of amniota, 112; nervous system, 112; coelenterata, 112; vermes, 1 13; mollusca, 114 ; arthropoda, 115 ; nature of invertebrate brain, 115, 116; chordata, 1 16 ; neurenteric canal, 116, 1 17 ; spinal nerves, 119 ; sympathetic system, 120 ; spinal cord, 121, 122 ; vertebrate brain, 122- 134 ; cranial nerves, 1 34-1 39 ; serial cranial sense organs and thymus gland, 1 39 ; sense organs, 141 ; olfactory organs, 142145 ; auditory organs, invertebrates, 145-147 ; chordata, 147-152; lateral line, 148 ; eyes of invertebrates, 1 5 2157; of vertebrates, 157-162; evolution of nervous system and sense organs, 164-167 ; segmental duct, 239, 249; external generative organs, 112, 261, 262; digestion, 273.

Epibole, 24, 33.

Epidermis, 98 ; human, 101.

Epididymis, 256, 257, 260.

Epigastric vein, 230, 234.

Epiglottis, 174, 182, 185.

Epicoracoid, 20 1.

Epiostracum, 99.

Epiphyses of vertebrae, 199.

Epiphysis cerebri, 128.

Epiphysial eye, 129, 162, 163.

Episterna, 201, 202.

Epitrichial layer of epiblast, 100, 241.

Epoophoron, 256, 257.

Equatorial plate, 19.

Ethmoid region of cranium, 207.

Ethmo-palatine ligament, 209.

Euaxes. See â€œ Rhynchelmis.-

Eustachian tube or recess, 139, 151, 179, 180.

valve, 221, 222, 236.

Eutheria, segmentation of, 44 ; allantois of, 90 ; placenta, 92 ; evolution of placenta, 96 ; Mullerian ducts, 253 ; foetal respiration, 276.

Eutima, planula of, 50.

Exoskeleton of invertebrates, 98-100,

192-194.

of vertebrates, 103, 192, 193.

Excretory organs, epiblastic, of larval mollusca, 108, 238 ; of adult mollusca, 108, 238 ; Malpighian tubules of insecta, in, [169, 238, 271; segmental duct, 239, 249 ; hypoblastic, amphipoda, 169, 186, 238, 271 ; mesoblastic, 70 ; invertebrates, 237 ; platyhelminths, 237, 238, 249 ; chsetopoda, 70, 238, 271 ; arthropoda, 70, 238, 27 1 ; mollusca, 70, 238, 239, 249 ; chordata, 70, 239 ; ascidians, 239 ; amphioxus, 239 ; vertebrata, 239-250, 271 ; pronephros, 239 ; mesonephros, 241 ; metanephros, 246 ; summary of development of vertebrate excretory organ, 248 ; epiblastic origin of segmental ducts, 239, 249 ; urogenital ducts, 250-259 ; urinary bladder, 87,

1 12, 259.

External carotid artery, 224-227, 231.

gills, 108, 109, 179.

iliac artery, 224, 232.

Extra-branchial cartilages, 208.

Extra-cellular digestion, 272.

Eye, 152; evolution of vertebrate eye, 77, 163-164; eyes of mollusca, 152, I54-IS7; arthropoda, 152-154, 157 ; vertebrates, 157-167; function of pigment, 157; epiphysial (pineal) eye, 129, 162, 163; â€œvertebrate- eyes of invertebrates, 152, 163 ; â€œ invertebrate - eyes of vertebrates, 129, 163 ; muscles, 192.

Eyelid, nerve supply, 137 ; development, 161, 162; of cephalopoda, 155, 156.

Facial nerve, 136, 138-141.

Falciform ligament, 213.

Fallopian tubes, 252-257.

â€œFalsification of embryological record,- 223.

Falx cerebri, 130, 13 1.

Feathers, development of down, 102 ; of pin or contour, 103.

Fenestra ovalis, 150.

rotunda, 150.

Fertilisation of ovum, 12, 277-280; starfish, elysia, 13 ; significance of, 14, 15.

INDEX.

321

Field-vole (Arvicola), inversion of blastoderm, 93, 94.

Fifth cranial nerve, 136, 138-141, 207.

ventricle, 132.

Fin-rays, 203.

Fiona, segmentation of, 23.

First cranial nerve, 137- 140.

Fishes, anterior commissure, 1 24 ; mucous canals of head, 139 ; auditory labyrinth, 1 50 ; accessory auditory apparatus, 1 50 ; operculum, 151 ; suspensorium, 152; eyelids, 162 ; yolk-sac in larvae, 1 7 1 ; blood supply to air-bladder, 182, 233, 235 ; goblet organs, 182 ; thyroid body, 184; thymus gland, 185; scales, 193 ; sclerotic bones, 193 ; ichthyopterygium, 204 ; cranium, 207 ; visceral arches, 209, 210 ; position of kidneys, 212 ; heart, 2 19 ; reduction of pharynx, 139, 178, 223; circulation, 232-235.

Fissurella, eye, 155.

Flagella, 98.

Flagellate infusoria, 2.

Flamingo (Phoenicopterus) feedingyoung

2 73 Flesh-maggot (Musca?), cell of, 8.

Flocculi, 126.

Fresh- water mussel (Anodonta), typhlosole, 175.

Frog, segmentation of egg, 21, 32, 33 ; blastopore, 41, 42 ; mesoblast, 64, 69 ; larval respiration, 87 ; urinary bladder, 87; stomodseum, no, ill; pituitary body, no, in ; nervous system, 1161 1 8 ; brain, 1 23-1 25 ; pineal gland,

1 1 7, 129, 163 ; mucous canals of head of larvae, 139; neuromerism of head, 14 1 ; posterior nares, 144 ; auditory ossicles, 152 ; auditory epithelium, 166; origin of nerves, 166, 167; intestine of tadpole, 176; caecum, 176; branchial chamber, 179 ; thyroid body, 184; thymus gland, 185; notochord, 186 ; vertebral column, 197, 198 ; pectoral girdle, 201 ; diaphragm, 213 ; heart, 220 ; aortic arches, 233 ; venous system, 234, 235 ; anterior abdominal veins, 230, 234 ; segmental duct, 239, 249 ; pronephros, 239-241 ; mesonephros, 242 ; epiblastic origin of segmental duct, 249.

Fronto-nasal process, 143, 144.

Foetal membranes, birds, 78 ; reptiles, 84 ; mammals, 84 ; summary of evolution of, 95 ; respiration, 276.

Food-yolk. See â€œYolk.-

Foramen caecum, 184, 185.

lacerum anterius, - medius, - pos terius, 207.

of Munro, 125, 128-134.

of Winslow, 212.

ovale of heart, 221, 222, 236, 237.

Fore-brain, 134.

vesicle, 122, 127, 1 34.

Fornix, 132.

Fossa Sylvii, 130, 131, 133.

Four-horned antelope (Tetracerus), placenta, 92.

Fourth cranial nerve, 1 37-140, 207.

ventricle, 123-126, 134.

Fowl (Gallus), egg, 9 ; segmentation of oosperm, 36-38 ; blastoderm, 39 ; primitive streak, 40, 43, 66 ; abnormal blastoderm, 42 ; mesoblast, 66 ; germinal wall or ridge, 67, 272 ; foetal membranes, 78 ; pro - amnion, 86 ; ciliated neural canal, 1 1 6 ; neurenteric canal, 1 1 7 ; nervous system, 118, 1 19; brain, 123, 125, 134; branchial sense organs, 139; nasal passage, 144; auditory organ, 147, 148; eye, 158, 160 ; thyroid body, 184 ; notochord, 187 ; muscles, 191 ; diaphragm, 213; heart, 2 1 7-2 1 9, 221 ; circulation of yolk-sac, 225, 226 ; pronephros, 241, 248, 252 ; mesonephros, 243-246, 248 ; metanephros, 246-249 ; Mullerian duct, 251, 252 ; segmental duct, 252 ; oviduct, 252 ; digestion of yolk in germinal wall, 272.

Fox (Canis vulpes), Gsertner -s duct, 257.

Funicular tissue, 278.

Furcula (of tongue), 183.

Furculum, 201.

Fusus, segmentation of, 24, 25 ; nervous system, 114, 165; digestion of yolk, 272.

Gartner -s duct, 257, 260.

Gall-bladder, 173.

Gands of Brunner, 173.

Ganoidei, nervous system, 1 18 ; cranial flexure, 1 23 ; cerebellum, 1 26 ; nasal pit, 143 ; auditory sac, 167 ; pancreas, 174; spiral valve, 175; pyloric cseca,

1 75 J pseudo-branch, 178; operculum, 179; air-bladder, 180, 181, 195; dermal plates, 193, 210 ; axial skeleton, 194-197 ; ribs, 199 ; clavicles, 201, 202 ; caudal fin, 203 ; cranium, 207 ; mandibular arch, 209 ; dermal bones of skull, 210; abdominal pores, 214, 258 ;

X

322

INDEX.

aortic arches, 235 ; Mullerian duct (oviduct) in male, 254 ; generative ducts, 258.

Gasserian ganglion, 136, 138-140, 207. Gasteropoda, otolith, 146 ; eyes, 154, 155 ;

cartilage of odontophore, 194.

Gastrula, 23, 268.

Gastrulation, 16, 21 ; ecliinodermata, 22 ; nudibranckiata, 23 ; cucullanus, 23 ; prosobrancks, 24, 25 ; cephalopoda,

26 ; vermes, 26 ; peripatus, 26, 27 ; Crustacea, 29; ampkioxus, 30; lamprey, newt, frog, 32, 33 ; ideal type, 33, 34 ; elasmobranck, 35 ; fowl, 37, 38 ; canary, 3 7, 38 ; nightingale, 43 ; rabbit, 46, 47 ; obelia, 48, 49 ; eutima, geryonia, 50 ; kydrozoa, 50 ; sponges,

5 Â°, 5 1 Gecko, vertebral column, 198.

Generative organ or gland, 4, 59, 70, 262-264.

Geniculate ganglion, 138.

Genital eminence, 174, 261, 262. Gephyrea, mesoblast of, 59 ; nepkridia, 237, 264.

Germ cells, 5, 190, 277.

Germinal epitkelium, 5, 212, 263.

spot, 7, 9.

-  - vesicle, 7, 8.

wall or ridge, 40, 67, 272.

Germ-plasma, 277, 278.

Geryonia, delamination of, 50.

Gills. See â€œRespiratory Organs.-

slits. See â€œ Visceral Clefts.-

Giraffe (Camelopardalis), placenta, 92. Gizzard, artkropoda, 1 10.

Glands, epiblastic, unicellular, 105 ; multicellular, simple and complex, 106, 107 ; mammary, 106, 107 ; provisional renal organ and pigment spots of mollusca, 108; of stomodseum, no; of proctodseum, 101, 112 ; pineal, 129, 162, 163; tkyrnus, 139, 184, 185; lackrymal, 162 ; kypoblastic, 169-171 ; endostyle, 172 ; gastric, liver, 173 ; pancreas, 174; intestinal, 175, 176.

of Bartkolin, 260.

of Lieb^rkukn, 273.

Glomerulus of pronepkros, 239, 240, 248 ; of mesonephros external, 244, 245 ; internal, 244-246. Glosso-pharyngeal nerve, 136, 138-141. Glottis, 1 81.

Goblet cells, 182.

Gonopkores, 263.

Gonads 26

Goose (Anser), neurenteric canal, 117. Gorgoniidse, csenenckyma of, 98, 194. Graafian follicle, 6.

Green gland, 238.

Growtk, 278, 279.

Gubernaculum, 260.

Guinea-pig (Cavia), inversion of germinal layers, 93, 95 ; epiblastic origin of segmental duct, 249.

Gurnards (Trigla), noise made by airbladder, 1 8 1.

Gustatory organs, 145-182 ; of amphioxus, 185.

Gymnodontes (Teleosts), air-sacs, 182. Gyrinopkilus (Urodele), vertebral column,

197.

Haemal arch, 195, 196.

Haemoglobin, 214, 269.

Haemolymph, 269.

Hair, development of, 101, 102, 107. Haliotis eye, 155.

Hatteria, pineal eye, 129, 163 ; abdominal splints, 193 ; vertebral column, 198. Head, 74, 75.

cavity, 138-140, 208.

fold, 39.

kidney, 239 ; of Teleosts, 240. See

â€œ Pronepkros.-

Heart, invertebrates, 215, 216 ; vertebrata, 21 7-223.

Hedonic glands, 112.

Helix, spermatozoon of, 4 ; provisional renal organ of, 108 ; eye, 155, 156. Hemiazygos vein, 228, 232, 233, 236. Hemickordata, notockord of, 186.

Hepatic artery, 236.

cylinders, 173.

portal system, 229, 234.

veins, 229, 231, 232, 234, 236.

Ilepato-pancreas, 171.

Heptanckus, visceral clefts, 139, 178; cranial segments, 140 ; absence of pericardial bodies, 184; branchial arches, 210.

Hernia, 262.

Heterocercal tail, 203.

Heteropoda, otocyst, 146.

Hexacoralla, csenenchyma, 98, 193. Hexanchus, visceral clefts, 178. Hexapoda, acoustic organ, 147. Hind-brain, 134.

brain vesicle, 122, 1 25, 1 34.

Hippocampus major, 1 30-1 32, 134. Hippolyte, auditory sac, 147. Histogenetic plasma, 277.

INDEX.

323

Holocephali ( see â€œChimera-), mandibular arch, 209 ; abdominal pores, 256.

Holothuroidea, respiratory trees, 177 ; dermal skeleton, 192.

Homocercal tail, 204.

Homoplastic, 222, 249.

Hoofs, 102.

Horn-cells of epidermis, 101 ; horn fibres of spinal cord, 120.

Horns of bovidae, 102 ; rhinoceros, 103.

Horse (Equus), spermatozoon of, 4 ; nipple of, 106 ; uterus masculiuus, 254 Hunt -s depression, 15 1.

Hydatid of oviduct, 251, 256, 257; of Morgagni, 254, 257, 260 ; of Wolffian body (mesonephros), 256.

Hydra, ovum of, 7 ; structureless lamella of, 53 > endodermal muscles, 176 ; origin of sexual cells, 263, 278 ; asexual reproduction, 278.

Hydrocorallinse, csenenchyma, 98.

Hydroids, spermatozoon, 4 ; planula, 49 ; adult condition, 71 ; nervous system, 1 13; origin of sexual cells, 262, 263. See â€œ Hydra - and â€œ Hvdrozoa.-

Hydromedusse, gastrulation, 48-50 ; gelatinous tissue, 71 ; digestion, 168.

Hydrozoa, primitive germ-cells, 6 ; morula, 50 ; radial symmetry, 71 ; cuticle or perisarc, 98. See â€œ Hydroids - and â€œ Hydromedusse.-

Hylodes, larval respiration, 87.

Hymen, 260.

Hyobranchial visceral cleft, 178.

Hyoid arch, 178, 206, 209, 210 ; artery of, 226, 227, 233, 234, 235.

of amphibia and amuiota, 210.

Hyostylic skull, 209.

Hyomandibular, 152, 177.

cleft, 178 ; cartilage, 208-210.

Hypoblast, 23-48, 168 ; organs derived from the hypoblast, digestive organs of invertebrates, 168-170; â€œliver- or hepato-pancreas, 170, 1 7 1 ; mesenteron of chordata, 171-176 ; pharynx, 1 72 ; stomach, 173 ; liver, 173 ; pancreas, 174; intestine, 174-176; endodermal muscles, 176 ; respiratory organs of invertebrates, 1 77 ; of chordata, 177180 ; intestinal respiration, 180 ; airbladder, 180, 181 ; lungs, 181, 182 ; tongue, 182, 183 ; thyroid body, 183, 184 ; thymus gland, 184, 185 ; gustatory organ of amphioxus, 186 ; excretory organs, 186 ; notochord, herni

chordata, urochordata, cephalochordata, 186 ; vertebrata, 186- 188 ; sub-notochordal rod, 188 ; urinary bladder, 18S ; digestion, 272, 273.

Hypodermis, 153, 154.

Hypogastric vein, 229 ; artery, 224, 232.

Hypoglossus nerve, 135, 140; multiple nature of, 14 1.

Hypopharyngeal ridge, 172.

Hypophysis cerebri, no, III, 185. See â€œ Pituitary body.-

Hyrax, placenta, 91 ; caeca, 170.

Hypural bones, 204.

Ianthina, segmentation of, 24, 25 ; veliger of, 99.

Iehthyopsida, anterior commissure, 13 1 ; innervation of lateral line of head, 139 ; process falciformis, 161 ; pharynx, 172; thymus, 185; sub-notochordal rod, 188 ; derma, 190 ; circulation, 232-235 ; pronephros, 240, 248 ; mesonephros, 248, 254 ; Mullerian ducts, 252 ; digestive glands, 272.

Ichthyopterygium, 204.

Iliac veins, 232, 234.

Ilium, 202.

Incus, 1 5 1, 152, 209.

Inferior (posterior), cardinal veins, 224, 228-230, 232, 234, 236.

vertebral vein, 229.

Infraclavicles, 201.

Infundibulum, 77, no, in, 124, 125,. 127, 128, 132, 134.

of lungs, 181.

Infusoria, artificial division, 278.

Inguinal ring or canal, 214, 262.

Ink-sac, 1 70.

Immigration (gastrulation), 48-50.

Inner-layer cells, 44.

Innominate vein, 220, 228, 232, 233, 235.

Insects, primitive germ-cells of, 6 ; segmentation of, 29 ; mesoblast of, 57 ; blastopore of, 58 ; coelom of, 58, 59 ; amnion, 96 ; salivary glands of, 106, no; stomodseum and derivatives, no; proctodseum and Malpighian tubules, in, 169, 238; auditory organ, 147; eyes, 153, 154; mesenteron, 169.

Insectivora, mesoblast, 68 ; placenta, 91 ; decidua reflexa, 93.

Interamnionic space, 95.

Intercalary (interhsemai and interneural) arches, 196.

Interclavicles, 201.

Intercostal veins, 228, 232.

324

INDEX.

Intermediate cell-mass, 191, 212, 243 245, 249, 250.

Internal carotid artery, 224, 227, 231.

Intervertebral discs and ligaments, 198, 199 Intestine, invertebrates, 169, 170 ; chordata, 171-176.

Intracellular digestion, 272.

Inversion of germinal layers in rodents, 93 Iris, nerve supply, 137, 161, 162 ; of cephalopoda, 155, 156.

Ischium, 202.

Isidinae, caenencliyma, 194.

Iter (a tertio ad quartum ventriculum) } 123-126, 134.

Jugular vein, 228, 229, 232-234.

Karyokinesis, 18-20.

Katabolism of protoplasm, 278-280.

Keel of sternum, 200, 201.

Kidney (proper) of vertebrates, 239,

246. See â€œ Metanephros.-

Labia majora, 260, 262.

minora, 262.

Labyrinthodonta, parietal foramen, 129; probable pineal eye, 163.

Laoerta. See â€œ Lizard.-

Lachrymal duct, 145, 162.

glands, 162.

Lacteals, 274.

Lamellibranchiata, shell-gland, 99 ; gills of, 108 ; nervous system, 1 1 5.

Lamina terminalis, 124, 125, 128, 129, 131, 132, 134.

Lamprey (petromyzon), segmentation of egg, 32 ; mesoblast, 63, 64, 69 ; fate of blastopore, 77 ; teeth, 105 ; stomodseum, no, hi ; pituitary body, no, III ; development of nervous system, 1 18 ; neuromerism of head, 141 ; pharynx, 172; gill - pouches, 178; thyroid body, 183 ; rudiments of pelvic fins, 204 ; visceral arches, 208 ; heart, 217; pronephros, 241. See â€œCyclostomi.-

Larvae (free), 78.

Larynx, 182, 1 74.

Lateral fin, 77, 1 92.

line, 139, 148.

ventricle, 124, 1 25, 128-134.

Leech (Hirudo), gastric diverticula, 168 ; skeleto-trophic tissue, 190 ; origin of blood-vessels, 214.

Leiodera, pineal eye, 163.

Lemurs, cerebral convolutions, 1 33.

Lemuroidea, placenta, 92.

Lens capsule, 162.

Lens of eye, invertebrates, 152-157 ; vertebrates, 158-164.

Lepidosteus, development of nervous system, 118; axial skeleton, 195-198; cranium, 207 ; pronephros, 240 ; connection between testis and mesonephros, 254, 258 ; oviduct, 258.

Leptocephalus, 266.

Leptoplana, segmentation of, 26 ; mesamoeboids of, 54.

Lepty chaster, direct development, 265.

Lepus. See â€œRabbit.-

Leucocytes, 190, 274 ; digestion by, 274.

Levator palpebrae superioris, nerve of,

137 Leydig -s duct, 255.

Ligamentum longitudinale superius, 195.

Limax, eye, 156 ; origin of ganglia, 165.

Limbs, musculature, 192 ; unpaired, 203 ; paired, 204.

Limpet (Patella), eye, 155.

Limulus, spermatozoa of, 3 ; respiration of, 109 ; lateral and central eyes, 153.

Lineus, segmentation of egg, 26 ; mesamoeboids of, 53, 54 ; mesenchymatous origin of nervous system, 165 ; origin of nephridia, 238 ; vascular system, 271.

Lingual artery, 233, 235.

Liquor amnii, 81.

Liver, so-called, of invertebrates, 1 70, 171 ; of chordata, 173, 174; blood supply, 229-237.

Lizard (Lacerta, except when otherwise mentioned), primitive streak, 41-43 ; blastopore, 44 ; mesoblast, 65, 69 ; proctodseum, 77 ; embryonic membranes of trachydosaurus, 84 ; connection of yolk-sac with oviduct in latter and cyclodus, 96} 273 ; proamnion, 86 ; scales of various lizards, 103, r 93 5 neurenteric canal, 1 1 7 ; pineal gland and pineal eye in various lizards, 129, 162, 163 ; auditory

ossicles (various), 1 5 1 ; closure of eyelids (various), 162 ; thyroid body, 184; thymus gland, 185; notochord, 186, 188 ; diaphragm, 213 ; aortic arches, 227 ; mesonephros functional with metanephros, 247 ; Wolffian tubules, segmental, 248 ; epiblastic origin of segmental duct, 250 ; Mullerian

INDEX.

325

duct (oviduct) in male, 254 ; persistent Wolffian duct, 257; bladder, 259; digestion of yolk in germinal wall, 272.

Lobi inferiores, 127.

Locomotory appendages, 202 ; invertebrates, 202, 203 ; chordata, 203, 204.

Loligo, shell-sac, 100 ; eye, 154.

Lophius, pronephros, 240.

Loricata, placenta, 91.

Lower-layer cells, 33, 34, 36.

Lumbricus. See â€œ Earthworm.-

Lungs, 78 ; invertebrates, 109 ; vertebrates, 1 81 ; homology, 182; blood supply, 222, 226-228, 231, 233, 2352 37 Lymnseus, veliger of, 99 ; stomodaeum, 1 10 ; radula sac, 1 10.

Lymph, 267, 269, 270 ; corpuscles, 274.

Lympatbic gland, 184, 240, 254, 274.

Macropus, communication between vaginal caecum and urogenital sinus, 253.

Macula acustica, 146.

Malleus, 15 1, 152, 209.

Mallotus, peritoneal ducts of ovary, 258.

Malpighian body, 237, 242, 244, 245, 246, 248, 249, 256 ; pronephros of teleostei, 240.

layer of epidermis, 100-101, 106.

tubules, hi, 169, 238.

Mammalia, ovary of, 6 ; spermatozoa, II, 14; segmentation blastodermic vesicle, 44 ; mesoblast, 68 ; umbilical cord, 84 ; pro-amnion, 86 ; epidermis, 101 ; hair, 101, 103 ; scales, 103 ; pituitary body, no ; sympathetic nervous system, 1 20 ; anterior commissure, 124; brain, 1 25-1 34; cerebellum, 126; corpora quadrigemina, 126, 127; posterior commissure, 129; cerebi*al hemispheres, 130 ; septum lucidum, 132; corpus callosum, 132; convolutions, 133 ; olfactory lobes, 133.

Mammals, superficial petrosal nerve, 136 ; neural segmentation (neuromerism) of head, 141 ; cochlea, 149 ; fenestra rotunda, 150; labyrinth, 150; scalse, 150; tympanum, 1 5 1 ; auditory ossicles, 150, 152 ; retinal blood-vessels, 161; nictitating membrane, 162; eyelids closed in some embryos, 162 ; pineal gland, 163; stomach, 173; digestive glands, 1 73, 174; intestine, 174-176 ; liver, 173 ; caecum, 176 ; visceral arches, 180 ; lungs, 181 ;

thyroid body, 184, 185 ; thymus gland, 184, 185 ; notochord, 186, 188 ; dermal skeleton, 193 ; vertebral column, 196, 198, 199; sternum, 200; pectoral girdle, 20 1 ; mandibular arch, 209 ; hyoid, 210 ; rotation of stomach, 212 ; omentum, 212 ; inguinal canals, 214 ; heart, 218-223 ; division of truncus, 222 ; ventricular septum, 222 ; aortic arches, 226, 235 ; venous system, 228233 ; circulation in foetus, 235-237 ; uterus, 253 ; vestigal structures of Wolffian body in adult, 256-257, 260 ; ureter, 258.

Mammary glands, 105, 106 ; of monotremes, 106, 107 ; evolution of, 107.

Man (Homo), spermatozoon, 4 ; foetal membranes, 88 ; placenta, 92, 93 ; epidermis, 101 ; mammary gland, 106,

107 ; muscle-fibres of sweat glands,

108 ; brain, 125 ; corpus albicans, 127 ; cerebral hemispheres, 130 ; fifth ventricle, 132 ; convolutions of cerebrum, 133 ; olfactory lobes, 1 33 ; persistence of vitelline duct, 1 7 1 ; pancreas, 174 ; valvulae conniventes, 176 ; caecum, 176 ; visceral clefts, 180, 183 ; laryngeal diverticula, 182 ; tongue, 183 ; thyroid body, 184, 185 ; thymus gland, 184, 185 ; rotation of stomach, 21 2 ; omentum, 212 ; diaphragm, 213 ; heart, 220-222 ; foetal circulation, 231 ; uterus, 92, 93, 253, 254; double uterus and vagina in anomaly, 253, 254 ; hydatid of Morgagni, 254, 256 ; uterus masculinus, 254; generative glands and ducts, 256, 257, 260.

Mandibular arch, 209 ; artery of, 1 5 1 , 226, 227, 233, 234, 235.

artery, 151, 235.

Manis, scales of, 103.

Mantle of mollusca, 99.

Manubrium sterni, 200.

Marsipobranchs = Cyclostomi. See â€œLamprey- and â€œMyxine.-

Marsupials. See â€œ Metatheria.-

Maturation of ovum, 9 ; significance of, 14 , 15 Meckel -s cartilage, 151, 206, 208, 209.

Mediastinum, 213.

Medulla oblongata, 123-126, 1 34, 135.

Medullary. See â€œ Neural.-

Medusae, mesoblast of, 53, 71, 189 ; auditory organs, 145.

Medusoids, 263.

Membrana adamantina, 105.

INDEX.

326

Membrane, bones of skull, 210.

of Descemet, 162.

Membranous cranium, 205.

portion of urethra, 262.

Menisci, 198.

Meroblastic oosperms, 48.

Mesamoeboids, 52-54, 57, 69, 189, 190, 269, 270, 274.

Mesencephalon, 130, 1 34.

Mesenchyme, 52-55, 69, 70.

Mesenteric vein, 229, 231, 232.

Mesenteries of actinozoa, 72.

Mesenteron, 25, 31 ; invertebrates, 1691 7 1 ; chordata, 171-176.

Mesentery, 21 1, 212, 270.

Mesoarium, 212, 256.

Mesoblast, 35, 50, 52 ; mesenchymatous mesoblast, 52; of sponges, 51, 52; ccelenterates, 53 ; echinoderms, 53 ; platyhelminths, 53 ; chaetopoda, 54 ; mollusca, 55 ; vertebrates (?), 67-69 ; mesothelial mesoblast echinodermata, 55; sagitta, 55, 59 ; brachiopoda, 55, 89 ; peripatus, 55, 59, 76 ; balanoglossus, 55, 59; chaetopoda, 56, 57, 59, 69 ; Crustacea, 57 ; tracheata, 57 ; amphioxus, 55, 59, 60; triton, 61 ; lamprey, 63 ; frog, 64 ; trionyx, 65 ; lizard, 65 ; fowl, 66 ; mole, 67 ; organs derived from mesoblast, indifferent mesoblast, 189, 190 ; dermal mesoblast, 191 ; muscular system, 190-192; dermal skeletal structures invertebrates, 192 ; chordata, 192, 193 ; endoskeletal structures, invertebrates, 193, 194; chordata, 194 ; vertebral column, 1 94-1 99 ; skeletogenous sheath of notochord, 194 ; vertebral arches and bodies, 195 - 199 ; fishes, 195, 197; amphibia, 197, 198; sauropsida, mammalia, 198 ; ribs, 199 ; sternum, 200 ; pectoral girdle, 200-202 ; pelvic girdle, 202 ; locomotory appendages, 202, 203 ; median fin, 203 ; caudal fin, 203, 204 ; paired limbs, 204; skull, 205-21 1; cranium, 205-207 ; visceral arches, 207-210 ; mandibular arch, 209; hyoid arch, 209, 210 ; branchial arches, 210 ; dermal bones, 210 ; body cavity, 21 1212 ; mesentery, 212 ; pericardium, 213; diaphragm, 213; pleurae, 213; abdominal pores, 213, 214; vascular system, 214-237 ; development of blood-vessels, 214, 215; formation of heart, 2 1 5-223 ; vascular system of vertebrates, 223-237 ; early embryonic

circulation, 224, 225 ; vitelline circulation, 226 ; foetal circulation, 226-230 ; allantoic, 230-232 ; circulation in ichthyopsida, 232-235 ; excretory organs, 237 ; invertebrates, 237-239 ; chordata, 239 ; pronephros, 239-241 ; mesonephros, 241-246 ; metanephros, 246247; urogenital ducts, 250-258 ; suprarenal bodies, 258, 259 ; generative organs, 262-264 ; digestion, 273274.

Mesoblastic (mesodermal) bands, 73 ; chaetopoda, 56, 57 ; arthropoda, 58 ; peripatus, 59.

Mesobranchial area of tongue, 183.

Mesocardium, 213, 215, 217, 218.

Mesocolon, 212.

Mesoderm, 51, 52, 69, 72.

Mesogastrium, 212.

Mesogloea (of coelenterata), 193.

Mesonephric duct, 251, 254.

(Wolffian) blastema, 245-249.

Mesonephros, 239, 241-246, 248, 249, 254-257 ; elasmobranchii, 242, 243, 245, 248, 249 ; teleostei, 246 ; amphibia, 242, 246, 248; fowl, 243-246, 248, 249 ; rudimentary portion in male elasmobranchii and amphibia, 255 ; vestigal structures in adult amniota, 256-257, 260.

Mesorchium, 212.

Mesorectum, 212.

Mesothelium, 52, 55-70, 21 1.

Metakinesis, 19.

Metamerism, 73, 74, 141.

-  - of body, 73.

Metanephric blastema, 246.

duct, 258.

Metanephros, 239, 246-249 ; fowl, 246249 ; incipient in elasmolranchia and amphibia, 247.

Metapterygoid, 209.

Metasternum, 200.

Metatheria, foetal membranes, 89, 90, 96 ; mammary glands, 107 ; cerebellum, 126 ; corpus callosum, 132 ; stomach, 173 ; Mullerian duct, 252 ; oviduct, 252, 253 ; vaginal caecum, 253 ; urogenital sinus, 252, 260.

Metazoa, 2; reproduction of, 3; kariokinesis, and direct nuclear division of, 19.

Metencephalon, 134.

Mid-brain, 126, 134.

Middle-brain vesicle, 122, 126, 134.

Milk, 273.

INDEX.

327

Mitrocoma, auditory organ, 146.

Mole (Talpa), blastoderm of, 46, 47 ; mesoblast of, 67, 68 ; inversion of blastoderm, 93; neurenteric canal, 1 1 7 ; optic vesicles, 164 ; pectoral girdle, 201.

Mollusca, segmentation of egg, 21 ; mesoblast, 55, 59, 69, 190 ; pericardium, 59, 70, 249 ; archiccelous cavities, 69, 70 ; shell-gland, 99 ; provisional renal organs, 108, 238 ; pigmeut spots, 108 ; respiratory organs, 108, 109 ; radula sac, 99, no, 170; nervous system, 113-116; osphradiura, 142; otocysts, 146; eyes, 152, 154-157, 163, 164; evolution of sense-cells, 166 ; alimentary canal, 170; salivary glands, 170; â€œliver,- 170, 171 ; velum, 99, 203; heart, 215 ; nephridia (organs of Bojanus), 70, 108, 237-239, 249 ; generative ducts, 70, 237, 264.

Monads, conjugation of, 14.

Monaster, 18.

Monkeys, cerebral convolutions, 133 ; Gsertner -s duct, 257.

Monodelphia. See â€œ Eutheria.-

Monomeniscous eye, 153.

Monostichous eye, 153.

Monotremata. See â€œ Prototheria.-

Mons veneris, 262.

Mormyrus, generative ducts, 258 ; abdominal pores, 258.

Morula, 50.

Moschus, placenta, 92.

Motoroculi, 137, 140.

Mouse (Mus), inversion of blastoderm, 93, 94 ; mammary gland of, 106, 107.

Mouth, 75.

Mucous canals of head, 138, 1 39.

layer of skin, 100, 101.

Mullerian duct, 251 ; elasmobranchs, 251, 252; amphibia, 251, 252; fowl, 251, 252; sauropsida, prototheria,

252 ; metatheria, 252, 253 ; eutheria,

2 53 5 various forms of mammalian uteri, 253 ; occurrence in male, 254, 255 ; recapitulation of evolution of Mullerian duct, 254 ; hydatids of, 252.

Mursenidse, abdominal pore, 258.

Murex, shell - gland of, 99 ; primitive kidney, 99 ; development of otocyst, 146 ; development of eye, 1 54; nervous system, 165.

Mus, inversion of blastoderm, 93, 94.

Muscle-plate, 192.

Muscles, 269 ; epiblastic, 108 ; innerva

tion of eye-muscles, 136, 137 ; endodermal muscles, 176 ; non-striated, 190; muscular system, invertebrates, 190, 191 ; chordata, 191, 192; histogenesis, 192 ; of eye, 192.

Mustelus, uterus, 95.

Myelencephalon, 134-136.

Myelon. See â€œSpinal Cord.-

Myoepithelial cell, 156.

Myotome, 199.

Myriapoda, antennae, 1 1 5 ; eyes, 153; mesenteron, 169.

Myrmecophaga, posterior nares, 144.

Myxine, nerves of, 120 ; diaphragm, 213 ; absence of glomerulus to pronephros, 248.

Nails, 102.

Nasal fossae, 137.

Nassa, segmentation of, 52.

Native bear (Phascolarctos), foetal membranes of, 89.

Nauplius, appendages, 1 1 5 ; proctodaeal respiration, 275.

Nautilus, otolith, 146; eye, 155, 156.

Nematocysts, 99.

Nematoda, spermatozoa of, 3, 4 ; mesoblastof, 59 ; otocysts, 146 ; nephridia, 23 7 Nemertea, relation to chordata, 74 ; ectodermal muscle-cells, 108 ; ciliated pits of, 109; nervous system, 1 1 3 ; otocysts, 146 ; gastric diverticula, 168 ; nephridia, 238, 249 ; vesicular connective tissue, 270.

Neomenia, nervous system, 1 15; rectal respiration, 177.

Nephric groove and canal, 250. Nephridia, 59, 70, 237-250.

Nephrostome, 237, 239, 249. 244.

Nerves, spinal, no.

Nervous system, 112-167, 276; evolution of, in chordata, 77, 167 ; development in invertebrates, 112-116; in chordata, 1 16-141.

Neural arch, 195, 196.

canal, 1 16.

crest or ridge, 120, 134-138.

groove, 1 1 6.

plate, 73 ; (unsegmented), 1 1 6-1 18,

164, 187.

pore, 1 17.

Neur-amniotic cavity, 94.

Neurenteric canal, 1 1 6.

Neuro-epithelial cell, 156.

Neuromerism, 141.

328

INDEX.

Newt (Triton), segmentation of, 32 ; mesoblast of, 61, 62, 69 ; axial hypoblast, primitive streak of, 77 ; epiblast of, 100; pituitary body, III; postanal gut, 1 17; cranial nerves, 138, 167 ; neural crest, 138 ; lateral line organs of head, 138 ; notochord, 186188 ; median fin, 203 ; urogenital organs, 255.

Nictitating membrane, 162.

nerve supply, 136.

Nightingale (Luscinia luscinia), blastopore, 43.

Ninth cranial nerve, 136, 138- 141. Non-retinulate eye, 153.

Nostril, epitrichial layer in, 101 ; development, 144.

Notidamus, vagus, 135 ; gill clefts, 139;

visceral arches, 208-210.

Notochord (unsegmented, 73), 186 ; of hemichordata, 186 ; of urochordata, 186 ; of cephalochordata, 186 ; of vertebrata, 186-188 ; significance of, 188; sheaths of, 194, 195 ; fate of, 195-199. Notochordal groove, 1 86.

tissue, 269.

Notodelphis, larval respiration of, 87. Nototrema, larval respiration of, 87. Nuclear division, 17 ; indirect (karyokinesis), 1 8, 19, 20 ; direct, 18, 19, 20. spindle, 17.

Nucleine, nucleoplasm. See â€œ Chromatin.-

Nucleus pulposus, 198.

Nudibraucliiatae, segmentation of, 21, 23 ; fate of blastopore, 76.

Nymphse, 260, 262.

Obelia, 2 7 ; segmentation and planula of, 48, 49, 268.

Obturator foramen, 202.

Occipital region, 20 7.

region of head, 141.

Octactiniae, spicules, 193.

Octopus, shell-sac of, 100.

Oculomotor nerve, 134, 139-141. Odontoblasts, 104.

Odontophora, cephalic eyes, 152, 1 55 ; renal organs, 238.

Odontophore, 1 10; cartilage of, 194. (Esophagus, gastropods, 25 ; actinozoa, 71; insects, no; invertebrates, 169, 170; chordata, 171-172.

Olfactory bulbs, 138. 1

lobes, 124, 125, 127, 130, 132, 133,

3 M.

Olfactory nerves, 124, 1 25, 1 33, 135,

I 37Â» 140, 143.

organ, 139; invertebrates, 1 42;

chordata, 142.

Oligochaeta, gastrulation, 26 ; mesoblast*

54, 57 Olivary bodies, 126, 1 34.

Omentum, 212.

Ommateal layer, 154.

Ommatidium, 1 55 -1 57.

Ommerythrine, 157.

Ornosterna, 20 1.

Omphalo-mesenteric vitelline veins, 85, 123, 218, 219, 224-226, 229-234 ; arteries, 223-226, 23 1,

Onchidium, dorsal eyes, 152, 163.

Ontogeny, 1.

Oogenesis, 280.

Oosperm, 3, 13, 14, 277.

Oosphere, 14.

Oospore, 14.

Operculum of fishes, 15 1, 1 79 ; of balanoglossus, 177.

Ophiacantha, direct development, 265.

Ophiuroidea, larval skeleton, 194 ; arms, 202 .

Ophthalmic division of the fifth nerve,

I35-I37 ganglion, 137.

Ophthalmicus superficialis, 135-136.

Opisthobranchs, pigment spot in veliger, 108.

Opisthoeoelous vertebrae, 196, 198.

Opossum (Didelphys), foetal membranes of, 89 ; oviducts, 253.

Optic chiasma, 124, 125, 127, 131, 134, 160.

cup, 158, 164.

lobes, 123-127, 134.

nerve, 137, 157, 160, 161,207; of

pineal eye, 163 ; of invertebrates, 153 - 156 .

thalamus, 124, 125, 128, 130, 131,

134 .

vesicles, 123, 127, 157-161, 164.

Orbito-sphenoid cartilage, 207.

Organ of Bojanus, 238.

of Corti, 149.

of Giraldes, 257, 260.

of Jacobson, 145.

Organs of lateral line, 139, 148.

Ornithodelphia. See â€œ Prototheria.-

Ornithorhynchus, oviducts, 253.

Os lenticulare, 152.

Osmerus, oviduct, 258.

Osphradium, 142.

INDEX.

329

Os tincae, 253.

Os uteri, 253.

Otoconia, 150.

Otocyst, vermes, 146 ; mollusca, 146 ; arthropoda, 146, 147 ; tunicata,

417.

Otolith, medusae, 145 ; vermes, 146 ; mollusca, 146 ; arthropoda, 147 ; tunicata, 147 ; vertebrates, 149. Outer-layer cells, 44.

Ovarian tubes of Pfliiger, 5.

Oviduct, 5, 254 ; uterine compartments in elasmobranchs, 95 ; reptiles, 84, 96 ; birds, 252 ; mammals, 96, 252-254. Ovum, 3, 4, 5, 7, 277-280 ; of vertebrates, 5 ; elasmobranchii, 5, 8 ; protopterus, 5 ; hydra, 7 ; sea-urchin, 7 ; cat, 7 ; fowl, 9 ; sauropsida, 8 ; structure, 8 ; egg-membranes, 9 ; maturation, 9-1 1 ; fertilisation, 12-15.

Pal^mon, heart, 216. See â€œPrawn.- Palatine, 209.

division of facial, 136.

Palato - quadrate or palato - pterygoid, 206, 209.

trabecular ligament, 209.

Palinurus, auditory sac, 147.

Pallial membrane, 99.

Paludina, fate of blastopore, 76; otolith, 146.

Pancreas, 1 74.

Parachordal, 205, 206.

Paradidymis, 260.

Para-epididymis, 257, 260.

Paramsecium, reproduction, 3.

Parapodia, 202.

Parasphenoid, 210.

Parenchymula, 27, 49, 267.

Parietal layer of peritoneum, 21 1 ; of pericardium, 2 1 3.

Paroophoron, 257, 260.

Parorchis, 255.

Parovarium, 256, 257, 260.

Parrot (Psittacus ?), neurenteric canal, 11 7 .

Pars olfactoria of anterior commissure,

124.

temporalis of anterior commissure,

124.

Parthenogenesis, 3, 15, 278.

Patella, eye, 155, 164.

Pathetic nerve, 137.

Peachia, endodermal respiration, 177. Pecora, placenta, 92.

Pecten, pallial eyes, 152, 163.

Pecten of eye, 161.

Pectinidae, pallial eyes, 163.

Pectoral girdle, 200-202.

Pelagia, direct development, 265.

Pelvic girdle, 202.

Penis, 260-262.

Peptic glands, 173.

Perameles, mammary gland of, 107.

Perennibranchiate amphibia, absence of pancreas, 174.

Peribranchial cavity of tunicata, 177.

Pericardium of mollusca, 59, 249 ; of chordata, 195, 213, 259; connection with nephridia, 237.

Perichondrium, 197, 201, 209.

Perilymph, 1 50.

Perineum, 257, 261.

Peripatus, segmentation and gastrulation, 26, 27, 267 ; mesothelium, 55 ; formation of somites, and origin of nephridia and generative organs, 59, 70 ; fate of blastopore, 75, 76 ; mesenteron, 169 ; segmental organs (nephridia), 59, 70, 238.

Perisarc, 98.

Perissodactyla, placenta, 92.

Peritoneal funnel, 240, 242, 244.

Peritoneum, 21 1, 212.

Petromyzon. ^â€œLamprey.-

Petrous ganglion, 138.

Phagocytes, 274.

Phalangista, mammary glands of, 107 ; vaginae, 253.

Pharynx of chordata, 1 7 1, 172, 177-180.

Phascolarctos, foetal membranes of, 89.

Phocaena, hyoid, 21c.

Phoronis, intracellular digestion in larva, 272.

Phylogeny, 2.

Physoclisti, air-bladder, 181.

Pigeon (Columba), feeds young, 273.

Pigment-cells of derma, 190 ; of eyes, I52-I57 Pigmented layer of choroid, 159-161.

Pig (Sus), placenta, 92 ; nipple of, 106 ; spinal cord of, 120; ear, 1 5 1 ; laryngeal diverticula, 182 ; tongue, 182 ; thyroid body, 184 ; thymus gland, 184 ; Gaertner -s duct, 257.

Pilosa, placenta, 91.

Pineal eye, 129, 162, 163.

gland, 124, 125, 128, 129, 132, 134,

162, 163.

Pipa, larval respiration of, 87.

Pituitary body, no, III, 124, 125, 128, 132, 134, 185.

330

INDEX.

Pituitary space, 205, 206.

Placenta, 84, 87, 91, 96 ; discoidal, 91, dome-shaped, 91 ; zonary, 91 ; diffuse, 91, 92 ; cotyledonary, 92 ; metadiscoidal, 92 ; of giraffe, tetraceros, moschus, 92 ; non-deciduate, 92 ; deciduate, 92 ; placental circulation, 224, 230-233, 236, 237.

Placental sac of birds, 82 ; of warbler,

S 3 Placoid scales, 103, 192, 193.

Plakula, 23, 268.

Planaria, otocyst, 146.

Planorbis, organ of Bojanus, 238.

Planula, 49-51.

Plasma of blood, 214, 2 1 5.

Plasmodium, 274, 276.

Platyhelminths, generative organs of, 6 ; segmentation of, 26 ; mesoblast of, 53? 59, 69 ; archiccelous cavities of, 69 ; repetition of internal organs of, 73 ; otocysts, 146 ; parenchyma, 189, 190 ; muscles, 190 ; nephridia, 237.

Pleurae, 213.

Pleuro-peritoneal cavity, 78-83, 213.

Pleuronectidae, absence of air-bladder,

181.

Pleuroperitoneal cavity, 68, 78.

Plicae aryepiglotticae, 185.

Plutei, spicules, 1 94.

Pneumatic duct, 181.

Pneumogastric ganglion, 138.

Poison glands, 1 06.

Polar cells, 10-15, 277-280.

cells (Polar bodies or globules), formation of, in asterias, 10 ; elysia, 10, 11.

Polyclades, origin of sexual cells, 263.

Polymeniscous eye, 153.

Polyodon, axial skeleton, 194, 196.

Polypterus, external gills of larva, 109 ; ventral orifice of pneumatic duct, 182 ; blood supply of air-bladder, 233, 235 ; oviduct, 258.

Polyzoa, mesoblast, 59 ; cuticle, 98 ; nephridia, 237 ; asexual reproduction, 278.

Pond-snail. See â€œ Lymnaeus.-

Pons Yarolii, 1 25, 126, 132, 134.

Poreuten, 67.

Porifera, spermatozoon, 4 ; gastrulation, 48, 50, 51 ; planula, 50 ; amphiblastula, 51 ; mesenchyme, 52, 69, 189 ; nervous system, 51, 165, 189 ; gastric diverticula, 168 ; archaeocytes,

189; spicules, 51, 189, 193; musclecells, 51, 189 ; germ-cells, 189, 262, 278 ; digestion, 274 ; asexual reproduction, 278.

Portal circulation, 234, 235.

vein, 229-232, 236

Portio facialis, 136.

profunda (or minor), 137.

Post-branchial nerve, 138.

clavicles, 201.

Posterior brain vesicle, 125, 134.

-  - (inferior) cardinal veins, 224, 228230, 232, 234, 236.

commissure, 124, 125, 1 29, 1 32,

134 *

nares, 144.

pelvic vein, 23 1.

vertebral vein, 228, 236.

Post-temporal bones, 201.

Prae branchial nerve, 138.

Praespiracular nerve, 136.

Prawn (Palaemon), auditory organ, 147 ; heart, 216.

Precaval vein, 224, 228.

Precoracoid, 201, 202.

Prehyoid aortic arch, 235.

Prenasal rostrum, 206.

Preoral lobe, 74, 76, 77, 164, 205. Preorbital process, 206.

Prepituitary region of head, 141. Presphenoid cartilage, 207.

Prespiracular ligament, 208.

Primates, vermiform appendix, 1 76. Primitive groove, 39, 40.

ova, 5 ; germ-cells, 6.

streak, 39 ; nature of, 41.

Pristiurus, 120, 191. See â€œDog-fish.- Proamnion of rabbit, 85 ; rodents, bat, dog, sauropsida, 86.

Procephalic lobes, 153.

Processus falciformis, 161.

'gracilis, 1 51.

vaginalis, 262.

Proccelous vertebrae, 198.

Proctodaeum, 76, ill ; invertebrates, hi, 169, 170; vertebrates, 112, 250, 261.

Proneomenia, intestinal respiration, 177. Pronephric duct, 239, 254.

Pronephros, 239, 254 ; amphibia, 239, 240, 248 ; teleostei, 240 ; lepidosteus, 240 ; elasmobranchii, 240, 241, 248 ; fowl, 241, 248 ; lamprey, 241 ; degeneration in fishes, 259.

Pronucleus, female, 11, 13 ; male, 13. Prosencephalon, 134.

INDEX.

331

Prosobranch gastropods, ova of, 6 ; segmentation of, 24, 25 ; provisional kidney of, 108 ; pigment spots, 108 ; nervous system, 1 14; digestion of yolk, 272.

Prostate gland, 260.

Prostatic portion of urethra, 262.

Protista, absence of nucleus in, 20.

Protocercal tail, 203.

Protoplasm of ovum, 8 ; of tissue-cells, 8, 19.

Protoplasmic continuity of animal cells, 267.

Protopterus, ovum of, 5 ; external gills, 109 ; hyoid aortic arch, 233.

Protospongia, 3.

Prototheria, eggs of, 46-48, 89 ; mammary glands of, 106, 107 ; cerebellum, 126; corpora quadrigemina, 127; pons, 127; corpus callosum, 1 32 ; cochlea, 149 ; vertebral epiphyses, 199 ; pectoral girdle, 201 ; Mullerian ducts (oviducts), 252, 253 ; urogenital sinus, 252, 253 ; ureter, 258; urinary bladder, 259 Pro to vertebra, 192.

Protozoa, 267 ; reproduction of, 2, 267, 279 ; nuclear division, 20 ; digestion, 272.

Pro ventriculus of insects, no, 169.

Pseudamnion of mustelus, 95.

Pseudobranch, 178, 233; artery of, 235.

Pseudochorion of mustelus, 95.

Pseudoccel, 69, 70.

Pseudo-vertebral region of head, 141.

Psolus, direct development in P. ephippifer, 265.

Pteropoda, otolith, 146.

Pterygo- quadrate, 208, 209.

Pubes, 202.

Pulmonary artery, 220-222, 226, 228, 233, 235-236.

plura, 213.

sacs (Arachnida), 109.

vein, 229, 234, 236.

Pulmonata, blastopore, 76 ; primitive renal organ, 108, 238 ; respiration, 109.

Purple snail. See â€œIanthina.-

Purpura, veligen, and origin of nervous system, 114, 165; digestion of yolk, 272.

Pylangium, 220.

Pyloric caeca, 175.

glands, 173.

Pyramids, 126, 134.

Quadrate, 151, 152, 206, 209.

Rabbit (Lepus), segmentation, blastodermic vesicle, 44, 45, 46 ; foetal membranes of, 85, 87, 90, 91 ; development of brain, 127, 132 ; eye, 161 ; visceral arches, 180; thyroid body, 184 ; pectoral girdle, 201 ; diaphragm, 213 ; heart, 216 ; epiblastic origin of segmental duct, 249, 250 ; vaginal septum, 253 ; uterus masculinus, 254 ; scrotal sacs, 262.

Radial symmetry, coelenterates, 71 ; ecliinodermata, 74.

Radix longa, 135, 137, 140.

Radula, 99, no.

Raja, pineal gland, 129.

Rana. See â€œ Frog.-

Ranodon, vertebral column, 197.

Raphd, 261, 262.

Rat (Mus decumanus), spermatogenesis, II, 12 ; inversion of blastoderm, 93, 94.

Rathke -s pouch, 174. See â€œ Hypophysis.-

RatitÂ®, sternum, 200.

Rectum, arthropoda, 109, III.

Recessus vestibuli, 148.

Rectus externus, nerve supply of, 136.

Renal organs. See â€œ Excretory Organs.-

portal system, 229, 234.

portal vein, connection with Wolffian tubules in anura, 242.

Reproduction, 277-280 ; in protozoa, 2, 3 ; in metazoa, 3-5, 277-280 ; asexual, 278, 279.

Reptilia, foetal membranes of, 84 ; epidermis of, 101 ; corpus callosum, 124, 132; anterior commissure, 124; cerebellum, 126; auditory ossicles, 15 1, 152; caecum, 176; lungs, 1 81 ; sclerotic bones, 193 ; vertebral column, 198 ; pleuro-peritoneal cavity, 213 ; ventricle, 222 ; aortic arches, 227 ; venous system, 228-230 ; mesonephros, 242 ; digestive glands, 273,

Respiratory organs, epiblastic, invertebrates, 108 ; anal, in arthropoda, 109, 177 ; chordata, 109 ; accessory, in teleostei, 109 ; hypoblastic, invertebrates, 177; chordata, pharyngeal, 177 180 ; intestinal, 180 ; air-bladder, 180,

181 ; lungs, 181-182.

Rete mucosum, 101.

Retia terminalia, 157.

Reticulum, 8, 19.

Retina, invertebrates, 153- 1 57; vertebrates, 158-164 ; histogenesis, 159. 160.

Retinophora, 154.

332

INDEX.

Retinidial cuticula, 156, 157.

Retinidium, 157.

Retinula, 153, 156.

Retractor of bvilb of eye, nerve supply of, 136.

Rhabdoms, 1 53 - 1 57.

Rhinencephala, 133, 134.

Rhinoceros, horn of, 103.

Rhinoderma, larval respiration of, 87.

Rhynchelmis, gastrulation, 26, 57 ; mesoblast, 57.

Ribs, 199; â€œtrue- and â€œfalse,- 200; â€œabdominal,- 200, 193.

Robin (Luscinia rubicula), development of feathers of, 102, 103.

Rodentia, pro-amnion of, 86 ; placenta, 91 ; inversion of germinal layers, 93 ; stomach, 173 ; vaginal septum, 253.

Rods and cones of retina, 159, 164.

Rosenmiiller -s organ, 256.

Rostrum, 200.

Rotifera, stomodseum and derivatives, no; nephridia, 237, 238.

Round ligament, 232, 260.

Ruminants, nipple of, 106 ; occipital region of, 141 ; stomach, 1 73; Gaertner -s duct; 257.

Saccobranchus, accessory respiratory organ, 1 09.

Sacculus hemisphericus, 1 49, 150.

Saccus endolymphaticus, 148.

Sagitta, generative organs of, 5 > 263 ; mesothelium of, 55, 59.

Salamander (Salamandra), spermatozoon of, 4 ; vertebral column, 197 ; Mullerian duct, 251.

Salivary glands, 105, Iio; of insects, 106, no; mollusca, 170.

Salmon (Salmo), air-bladder, 180; diaphragm, 213 ; abdominal pore, 258.

Salmonidae, genital pore, 258.

Sauropsida, eggs, 8, 9 ; primitive streak, 42 ; pro-amnion, 86 ; pons Varolii, 126 ; cerebral hemispheres, 129 ; anterior commissure, 131 ; auditory labyrinth, 150 ; auditory ossicles, 1 5 1, 152; pecten of eye, 16 1 ; eyelids, 162 ; pineal gland and eye, 163 ; axial skeleton, 196-198 ; Mullerian ducts, 252 ; ureter, 258 ; digestion by epiblast of blastoderm, 273.

Scala media, tympani, vestibuli, 150.

Scales, reptiles, 103, 1 93 ; placoid, 103, 192 ; manis, 103 ; of teleosts, 193 ; chaetopoda, 202.

Scapula, 201.

Scent glands, 106.

Schneiderian membrane and folds, 143.

Schizopoda, auditory orgau, 147.

Scincus, scales of, 103.

Sclerotic bones, 193.

of cephalopoda, 155, 156 ; of vertebrates, 160-162.

Scorpion, direct nuclear division in, 18, 19 ; pulmonary sacs of, 109 ; central and lateral eyes, 153.

Scrotum, 260, 262.

Scutee of birds, 103.

Scutes of crocodiles, 103, 193 ; armadillos, 103, 193 ; lacertilia, 193 ; caecilia,

193 Scy Ilium, 121, 143, 144, 196, 208. See â€œDog-fish.-

Scyphistoma, 265.

Scyphomedusae, 72 ; origin of middle layer, 53 ; stellate cells in disc, 189 ; direct development, 265.

Scyphopolypi, 72.

Sea-anemone. See â€œ Actinozoa.-

anatomy of, 72. See â€œActiniae-

and â€œ Actinozoa.-

Seals (Phocidae), decidua reflexa, 93.

Sea-urchin, ovum of, 7 ; mesamoeboids of, 53 ; external muscles, 190 ; larval skeleton, 194.

Sebaceous glands, ioi, 107, 112.

Secondary mesoblast of crayfish, 57.

Second cranial nerve, 137.

Seessel -s pouch, 174.

Segmental duct, 239-252, 254 ; epiblastic origin, 239, 249, 250 ; amphibia, 239,

240, 249 ; fishes, 240, 241, 249 ; fowl,

241.

organs, 238, 250.

tubules, 242-250, 254 ; secondary

tubules, 242, 245-248 ; testicular network of elasmobranchii and amphibia, 2 55> 256.

Segmentation, 16, 267, 268 ; elysia, 16, 17, 20, 21 ; frog, 21 ; mollusca, 21, 24, 25, 26 ; vermes, 26 ; peripatus, 26, 27 ; Crustacea, 27, 28, 29 ; insects, 29 ; amphioxus, 29 ; bird, 31 ; lamprey, newt, frog, 32 ; sturgeon, 33 ; ideal type* 33 34 ; elasmobranch, 33, 35 ; fowl, 36; rabbit, 43, 44,45-46; hypothesis of mammalian segmentation, 47.

cavity, 21, 2 1 5, 269 ; nucleus, 13.

Segmentation of body, metamerism, 73, 74, 141 ; of head, 137-141 ; of vertebral column, 199.

INDEX.

333

Segmented worms. See â€œ Chaetopoda.- Selachians, abdominal pores, 258. See â€œ Elasmobranchii.-

Semicircular canals, 149.

Semilunar valves, 222.

Seminal globules or granules, II, 14. Sense organs, 98, 14 1, 142 ; serial cranial sense organs, 1 37-140; tactile organs,

141 ; olfactory organs, invertebrates,

142 ; chordata, 142-145 ; gustatory organs, 145 ; auditory organs, invertebrates, 145-147; chordata, 147-152; organs of lateral line, 148 ; visual organs, invertebrates, 1 52-1 57 ; vertebrates, 157-162 ; epiphysial (pineal) eye, 162, 163 ; evolution of vertebrate eye, 163-164 ; evolution of sense organs, 164-167 ; gustatory organ of amphioxus, 185 ; taste buds, 182.

Seps, pineal eye, 163.

Septum aorticum, 22 1.

inferius, 221.

intermedium, 221.

lucidum, 125, 132.

pellucidum, 125, 132.

superius, 22 1.

transversum, 2 1 3.

Serous membrane of vertebrates, 81-96 ;

of insects, 97.

sacs, 213, 262.

Serpula, mesoblast of, 54, 56 ; gills of,

108 ; cartilage in gills, 194.

Setse, 146, 202.

Seventh cranial nerve, 136, 1 38- 14 1. Shagreen, 192.

Sharks, thymus gland, 184 ; connection between embryo and parent, 273. Sheep (Ovis), development of brain, 128, 131 ; branchial sense organ, 139; auditory organ, 148 ; thyroid body, 184. Shell, brachiopoda, 99 ; m oil u sea, 99.

gland, of mollusca, 25, 99, 100 ; of

Crustacea, 238.

Shrimps, auditory organ, 147.

Siluroidea, accessory respiratory organs,

109 ; accessory auditory apparatus, 150, 181 ; pancreas, 174.

Siren, external gills, 179.

Sirenia, placenta, 92 ; absence of vertebral epiphyses, 1 99.

Sinus prsecervicalis, 180, 183.

â€¢ reuniens, 221.

terminalis, 85, 86, 88, 91,119, 225,

226.

Sinus venosus, 219, 221, 224, 225, 234. Sixth cranial nerve, 136, 139- 140.

Skeletal tissues, 269.

Skeletogenous cells, 269.

sheath of notochord, 194.

Skeleto-tropliic tissue, 190, 269.

Skin invertebrates, 96 ; chordata, 100.

Skull, 205-21 1.

Slime glands, 106.

Sloth (Pilosa), stomach, 173.

Smelt (Osmerus), oviduct, 258.

Snail, spermatozoon of, 4, 11.

Snakes (Ophidia), scales of, 103 ; pituitary body, III; closure of eyelids, 162 ; aortic arches, 227, 228 ; persistent Wolffian duct, 257.

Somatopleur, 68, 78, 21 1.

Somite, 59, 61, 192, 21 1.

Spermatoblast, 11, 14.

Spermatocyst, 11.

Spermatogenesis, 280 ; in rat, snail, earthworm, elasmobranchs, 11, 12.

Spermatozoa, 1 1 - 15, 277-280; of nematoda, 3, 4 ; arachnida, 3 ; limulus, 3 ; Crustacea, 3 ; sponge, 4 ; hydroid, 4 ; crayfish, 4 ; snail, 4, 1 1 ; electric ray, 4 ; salamander, 4; horse, 4 ; man, 4 ; rat, 11, 12 ; earthworm, 11, 12; elasmobranchs, II, 12.

Sperm blastophore, 11, 14.

morula, 11, 14.

Spermosphere, 11, 14.

Spermospore, 14.

Sphenoidal fissure, 20 7.

region of cranium, 207.

Spicules, alcyonaria, 98 ; sponges, 189, 193 ; echinoderms, 1 90, 192.

Spider (Arancida), mesoblast, 57 ; pulmonary sacs, 109 ; thoracic ganglia, 1 16 ; eyes, 153 ; heart, 216.

Spinal accessory nerve, 135.

cord, development of, 116-119;

histogenesis of, 12 1, 1 23-1 25.

Spinning glands, 106.

Spira, 19.

Spiracle, 136, 178, 233 ; artery of, 235.

Spiracular cartilage, 208, 210.

Spiral valve, 175 ; vein of, 234.

Splanchnopleur, 68, 78, 21 1.

Spondylus, pallial eyes, 152, 163.

Sponge. See â€œ Porifera.-

Spongy portion of urethra, 262.

Sporosacs, 263.

Squamatn, placenta, 91, 92.

Squamosal, 1 5 1.

Squid. See â€œ Loligo.-

Stapes, 15 1, 152.

Starfish, formation of polar cells, 10 ;

334

INDEX.

fertilisation of ovum, 13 ; archenteric diverticula, 56; stomodaeum, no; nervous system, 113 ; arms, 202. Sterno-clavicular ligament, 200, 201. Sternum, 200-202.

Stigmata of tunicata, 178.

Stolons, 278 ; of hydroids, 262.

Stomach, invertebrates, 169, 1 70; chordata, 1 7 1 - 1 74 ; man, 212.

Stomodaeum of actinozoa, 71 ; scyphomedusae, 72, 76, no; chordata, no; structures derived from, no ; invertebrates, 169, 170.

Stratum corneum, 101.

Malpighii, 101.

Sturgeon (Acipenser), segmentation of egg, 33 ; taste-buds in oesophagus, 182 ; sub-vertebral ligament, 188 ; axial skeleton, 194, 196 ; clavicles, 201 ; renal ducts and oviducts, 258. Sturio. See â€œ Sturgeon. -

Stylonychia conjugation, 3.

Subclavian artery, 224, 226, 227, 231, 236 ; vein, 224, 228-229, 232, 233. Subintestinal vein, 223, 233, 234. Sub-notochordal rod, 188, 191, 240, 242. Sub- vertebral ligament, 1 88.

Subzonal membrane, 79, 81, 84, 87, 90. Sudoriferous glands, 107.

Suina, placenta, 92.

Sulci of cerebral hemispheres, 133. Superficial petrosal, 136.

Superior (anterior) cardinal veins, 224, 225, 228, 229, 231-233, 234.

intercostal veins, 232.

oblique eye-muscle, nerve of, 137.

(anterior) vertebral veins, 228, 229.

Supra-branchial nerve, 138.

clavicle, 201.

commissura, 128.

pericardial bodies, 184.

Suprarenal bodies, 240, 258-259. Suspensorium, 152, 209.

Sweat glands, 106 ; muscle fibres of, 108. Sympathetic nervous system, 1 20, 121,259. Symplectic, 152.

Synangium, 220.

Syncytial segmentation, 26, 267. Systemic aortic arch, 233.

Tactile organs, 14 1.

Tail, 74, 75, 77.

Tail-fold, 39.

Taste-buds, 182.

Teeth, development of, 103 ; milk-teeth, 104 ; horny teeth, 105.

Tela choroidea, 1 25, 129.

Teleostei ( see Preface), accessory respiratory organs, 1 09 ; pituitary body, III; nervous system, 118 ; cranial flexure, 123 ; lobi inferiores, 127 ; reduction of branchial clefts, 139, 178 ; nasal sac, 143 ; accessory auditory apparatus, 150, 181 ; hyomandibular, 152, 178 ; epidermis, 166 ; origin of auditory sac and optic vesicle, 167 ; pancreas, 174; spiral valve, 175; pyloric caeca, 175 ; pseudobranch, 178 ; operculum, 179 ; intestinal respiration, 180 ; air-bladder, 180 ; respiratory functions of air-bladder, 181 ; scales, 193; parosteal bones, 193, 210; sclerotic bones, 193 ; vertebral column, 196, 197 ; ribs, 199 ; pectoral girdle, 201, 202 ; caudal fin, 203 ; cranium, 207 ; mandibular arch, 209 ; dermal bones of skull, 210 ; diaphragm, 213 ; abdominal pores, 214, 258, 264 ; heart, 218 ; conus arteriosus, 220 ; aortic arches, 235 ; pronephros, 240, 248 ; mesonephros, 240 ; generative ducts, 258 ; degeneration of pronephros, 259.

Telolecithal ova, 8, 271 ; segmentation, 23, 3 r > 33 5 gastrulation, 24, 33.

Temporal lobe, 124.

Tenth cranial nerve, 135, 1 38-141.

Testicular network, 255, 256.

Testis (testicle), 5, 260, 262, 263.

Tetraceros, placenta, 92.

Thalam encephalon, 1 24-12 5, 1 27- 1 34, 1 58.

Thelyblast, 14.

Third cranial nerve, 1 37, 139-141.

ventricle, 124-125, 128-134.

Thoracic cavity, 213.

Thorax (insects), 147.

Thread-cells, 99.

Thyroid, in, 172, 183, 185, 210.

Thyroidean visceral cleft, 178, 184 ;

artery of, 235.

Thymus gland, 139, 184, 185.

Toad. See â€œ Bombinator,- â€œ Bufo.-

Tongue, 182-184.

Tortoise (Testudo), anal sacs, 112.

-  - shell, 103.

Toxopneustes, 7. See â€œ Sea-Urchin.-

Trabeculae cranii, 205, 206.

Trabecular region of head, 14 1.

Trachea (of lungs), 181, 182, 174.

Tracheae, evolution of, 109.

Tracheate arthropoda, mesoblast of, 57 ; respiration of, 1 09 ; Malpighian tubules, 169.

Trachydosaurus, embryonic membranes of, 84, 96.

INDKX.

335

Trachy medusae, auditory organ, 145, 146. 1 Trager, 95.

Tragulina, placenta, 92.

Transitional cells of epidermis, 101. Trichites (of sponges), 193.

Trichoplax, 23.

Trigeminal nerve, 136, 138-141, 207. Trionyx, blastopore, 44 ; formation of blastopore, 65, 69 ; notochord, 186188. See â€œ Chelonia. -

Tripoblastic organism, 268.

Triton. Â£eeâ€œNe\vt.-

Tritylodon, parietal foramen, 129. Trochlear nerve, 137, 139- 141.

Trout (Trutta), thymus gland, 184 ; pronephros, 240.

Truncus ateriosus, 220-222, 226, 227,234. Tuber cinereum, 127.

Tuberculum impar, 183.

Tubulidentata, placenta, 91.

Tunica vaginalis, 21 3.

Tunicata, mesoderm of, 60; neural canal,

1 17 ; neural pore, 1 17 ; auditory organ, 147, 148 ; pineal gland, 163 ; pharynx (branchial sac), 172; endostyle, 172 ; fold in intestine, 175 ; asexual reproduction, 278 ; visceral clefts, 177 ; atrium, 177, 178 ; notochord, 1 86, 1 88. Turbellaria, epidermal rods, 99 ; gastric diverticule, 168 ; origin of sexual cells, 263 ; intracellular digestion, 272. Turbinal bones, 143.

Turtle, pharyngeal respiration, 180. See â€œ Trionyx.-

Twelfth cranial nerve, 135, 140, 141. Tylopoda, placenta, 92.

Tympanic cavity, 1 5 1 .

Tympanum of hexapoda, 147 ; elasmobranchs, 150 ; amphibia, mammals, 151 ; teleosts, 181.

Typhlosole, 175.

Umbilical artery, 231, 237; vein, 233, 237.

cord, 84, 259.

vesicle, 78, 231.

Umbilicus, 171-174.

Urachus, 87, 259, 260.

Ureter, 246, 247 ; ureters of elasmobranchia and amphia, 256 ; amniota, 258. Urethra, 260, 261 ; various regions of â€œ urethra - of male, 262.

Urinary bladder, 87, 112, 188, 259, 260; homology of, 87, 259 ; of fishes, 259 ; amphibia, 87, 230, 259 ; of amniota, 259, 260 ; veins, 230, 234. Urochordata, notochord of, 186.

Urocyst, 87, 230, 259, 276.

Urodoeum, 112, 250.

Urodela, epiblast of, 100, 1 66 ; external gills of larvae, 109 ; pineal gland, 129 ; mucous canals of head, 138, 139; reduction of visceral clefts, 1 39 ; columella, 152 ; respiratory organs, 1 79 ; vertebral column, 1 97-198 ; median fin, 203 ; tail, 204; hyoid, 210 ; aortic arches, 233-235 ; segmental duct, 239; urogential apparatus, 255, 256. Urogenital ducts of vertebrates, 250 ; segmental duct, 251 ; Mullerian duct, 251 ; oviduct, 251, 252 ; of metatheria, 25 1 ; of eutheria, uterus, 252254; Wolffian duct, 254 ; vas deferens, 256 ; generative ducts of ganoids and teleosts, 258 ; metanephric ureter, 258 ; urogenital sinus, 252. 253, 258, 259 ; urethra, 260.

sinus, prototheria, 252, 253 ; meta tlieria, 253 ; eutheria, 253-262. Urostyle, 198, 204.

Uterine glands (aud milk), 90.

Uterus, 5 ; of elasmobranchs, 95 ; of lizards, 84 ; of mammals, 84, 87, 9294, 96, 252 ; uteri of metatheria, 252, 253 ; of eutheria, 253, 254, 260 ; human anomaly, 253, 254; bipartitus, 253; duplex, 253 ; simplex, 253.

Uterus masculiuus, 254, 257, 260, 262. Utriculus, 149.

Vagina, 252-254 ; vaginae of metatheria

252, 253 ; vaginal caecum, 253; vagina of eutheria, 253, 260, 261 ; vaginal septum, 253 ; double human anomaly,

253 , 254.

Vagus nerve, 135, 138-141, 207.

Valves of heart, 219-223 ; of conus arteriosus, 222.

Valvulae conniventes, 176.

Vane of feathers, 102, 103.

Varanus, pineal eye, 163.

Vasa aberrentia, 256, 257, 260.

efferentia, 237, 254-257.

Vascular system, 70, 214; development of blood-vessels, 2 14, 270, 27 1 ; formation of heart, invertebrates, 215; vertebrates, 217, 270; development of vascular system in vertebrates, 223 ; early stages in embryonic circulation, 224 ; vitelline circulation, 226 ; later stages of vitelline circulation, 226 ; venal portal system, 229 ; hepatic portal system, 229 ; allantoic circulation, 230 ; circulation in ichthyopsida, 232 ; summary of history of aortic

336

INDEX.

arches, 235 ; changes undergone in circulation of foetal mammals, 235.

Yas deferens, 256, 262.

Vasifactive tissues, 269.

Veliger larva of mollusca, 99, 108, 114.

Velum (Mollusca), 99, 203 ; medusae, 145, 146.

Vena cava, inferior, 220-222, 229-233, 234, 236 ; superior, 220-222, 228, 229,

233-236.

Venae advehentes, 230, 231, 236.

reheventes, 229, 230, 231, 236.

renales advehentes, 228, 229.

Ventricular septum, 220-223.

Ventricle of heart, 1 95, 219, 224.

Vermes, brain of, 1 15 ; eye, 156 ; asexual reproduction, 278.

Vermiform appendix of caecum in primates and wombat, 1 76.

Vermis of cerebellum, 126.

Vertebral artery, 226, 227.

column, 194 ; fishes, 195 ; amphibia,

197 ; sauropsida, 198 ; mammalia,

198 ; evolution of, 199.

region of head, 14 1.

rudiment, 191, 192.

Vertebrates, germinal epithelium, 5 ;

primitive germ cells, 6, 263 ; eggmembranes, 9 ; completion of gastrulation, 48 ; mesoblast, 68-70 ; metamerism, 73 ; fate of blastopore, 76-78 ; evolution of nervous system, 77 ; foetal appendages, 78 ; aquatic larvae, 87 ; yolk sack, 95 ; epiblast, 100-102 ; pituitary body, 1 10; proctodaeum, III ; cloaca, 112 ; neurenteric canal,

1 16; brain, 122; nasal sacs, 143; posterior nares, 144; ear, 148-151; eyes, 157 ; hypothetical evolution of eyes, 77, 163; liver, 1 73 ; pancreas, 174; intestine, 175 ; gill-clefts, 178; notochord, 186 ; derma, 190 ; vertebral column, 194, 195 ; sacral ribs, 200; pectoral girdle, 201 ; locomotory appendages, 202 ; paired limbs, 204 ; skull, 205 ; mesentery, 212 ; formation of blood, 215; heart, 217; vascular system, 223 ; nephridia or excretory organs, 237, 239, 248, 250 ; mesonephros, 242 ; urogenital ducts, 250, 264 ; generative organs, 263, 246 ; digestive connective tissue, 270 ; digestion, 272 ; function of leucocytes, 274.

Vesicula seminalis, 260.

Vesicular cells of mollusca, 270. Vesiculate hydroraedusae, auditory organ of, 145.

Vestibule, 259.

Visceral arches, 207.

clefts, 73, 77, no, 135, 138, 141,

117-180, 183.

layer of peritoneum, 2 1 1 ; of pericardium, 213.

Visual organs, 152-167.

pigment, 153, 157.

Vitellaria, 6.

Vitelline arteries, 223-226, 231.

duct, 17 1 - 1 75, 231; occasional

persistence in man, 17 1 ; and birds, 172.

membranes, 9, 81.

veins, 85, 123, 218, 219, 224-226,

229, 234.

Vitreous body, 155.

humour, 162.

Viviparous lizards, 84.

Vomer, 210.

Vorticella, reproduction of, 3, 14.

Vulva, 260.

Warbler (Sylvia), embryonic membranes of, 83.

Water-beetle, larval eye, 153.

White body of cephalopod eye, 114, 156. Wolffian blastema, 245-249.

body, 70, 239. See â€œMesonephros.-

duct, 243-247, 251, 254-260 ; testicular network, 255 ; rudimentary portion in adult, 256-257, 260 ; vas deferens, 256.

ridge, 204.

tubules. See â€œSegmental tubules.-

Wombat (Phascolomys)j vermiform appendix of caecum, 176.

Worms. See â€œ Vermes,- i c Chaetopoda,- â€œ Platyhelminths. -

Xiphoid, 200.

Yolk, 5, 6 ; of birds, 6, 37 ; digestion of, 272 ; absorption of yolk by gillfilaments of embryo elasmobranchs, 1 79. Yolk glands of platyhelminths, 6.

P lug, 33.

pyramids, 28, 29.

sac, 39, 46, 78-96, 231.

Zona pellucida (Zona radiata), 7, 9, 43, 84.