Talk:Book - Experimental Embryology (1909)

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HENRY FROWDE, M.A. Publisher TO THE IINIVIZRSITY of OXFORD LONDON, EDINBURGH, New York TORONTO AND MELBOURNE


Index Of Subjects

Abnormality, 1; produced by centi-ifugalizing, 88; by shocks, 89; by perpetual rotation, 90; by sound vibrations, 90; by electric currents and magnetism, 91; by heat and cold, 98 sqq. ; by desiccation, 115; by sodium chloride and other substances, 199 sqq., 132; significance of forstudy ofvariation, 155, 156; produced by irregular distribution of chromosomes, 263266.

Absorption of water, sea Water.

Absorption, by cells, 5.

Abstraction of water, withdrawal of.

Acanthocystis, 48.

Acceleration of development by weak electric currents, 91; in violet light, 94, 95; at high temperatures, 97, 105; in pure oxygen, 110; by pilocarpine, 151 ; by sodium hydrate, 151.

Acclimatization, 290; to heat, 100; to hypertonic solutions, 117; to salt, 136.

Acids, 122.

Acrosome, 123.

Adaptation, 290.

Aggregates of cells, 5 sqq.

Aggregation of cells, 5.

Agitation, mechanical, 89.

Albumen, as amedium, 45, 53 ; drops of, 54 ; of Hen’s egg, 115.

Alcohol, 132.

Alcyonaria, 55.

Alkalinity, need of, 150, 151.

Alkaloids, in Amphibian eggs, 120, 123 ; on Sea-urchin eggs, 126 sqq. ; on Hen's egg, 132.

Allantois. fused with somatopleure, 9; sticks to yolk sac in eggs that are not turned, 89.

Allelomorphs, 266.

Allolobophora, 251.

Alteration of potentiality, see Potentiality.

Alteration in shape of cells, 5, 29, 48.

Alternation in direction of division in ‘ spiral’ cleavage, 25, 28.

Amblystoma, absorption of water by

see Water,

tadpole, 58; effects of cold, 100; eifect of solutions, 120; acclimatized to salt, 186; formation of lens, 275.

American Periwinkles, 71.

Ammonia, on Hen’s egg, 132; effect on nuclei, 135.

Ainnion, not formed at low temperatures, 104; folds of, 9; abnormal, 110.

Amniota, archenteron of, 8; oviduct of, 9.

Amoeboid processes in blastomeres, 53 ; movements of polar lobe, 227.

Amphiaster, see Spindle.

Amphibia, oviduct in, 9; absorption of water by tadpoles, 58, 115; influence of electric current on, 91; effect of various solutions on, 119—123, 133-135; efects of heat and cold on, 97-101 ; acclimatized to heat, 100 ; to salts, 136 ; isolated blastomeres of, 159 sqq.

Amphikaryotic, 267.

Amphioxus, club-shaped gland, 6; medullary plate, 8, 133 ; segmentation of, 22, 26, 28, 47; in certain solutions, 140; potassium necessary to adult, 147; isolated blastemeres of, 179, 180 ; double embryos, 180.

Amphitrite, segmentation of, 26; parallel polar furrows, 46; artificial partheuogenesis, 124.

Anachronism of first furrow in Frog, 161, 165.

Analytical theory of Driesch, 280286.

Anaistomoses of cell-aggregates, 6, 2 3.

Ancncephaly, 119.

Anenteria, 106.

Angles between contact surfaces in systems of lamellae, 43; in segmenting ova, 47, 53; between egg axis and first furrow in forcibly inverted Frog's eggs, 82; between plane of symmetry, first furrow, and sagittal plane, 165-167.

Animal cells, see Cells.

Animal pole, near anterior end of INDEX OF

embryo, 165 ; apical organ formed at, 244.

Anion, 136.

Annelids, germ-bands of, 5 ; nephridia and coelom, 6; nerve-ganglia of, 11; segmentation of, 25, 48; symmetry of egg and that of embryo, 241.

Antecedent conditions, 283.

Anledon, pressure, 37 ; heterogeneous cross-fertilization, 262.

Antennularia, 272, 273.

Antidotes to poisons, 135, 136.

Antitoxicity, 136.

Apical body, 123.

Apical organ of Echinoids, 144; of Pilidium, 204-206 ; of Ctenophora, 211; of Patella, 218; of Dentalium, 224-225 ; of Molluscs and Annelids, 244.

Aplysia, 46, 47.

Aplysia depilans, 30; limacina, 30, 45.

Arachnids, 24.

Arbacia, suppression of cell-division, 56, 117 ; artificial parthenogenesis, 108 ; need of oxygen, 112 ; effect of atropine, 131 ; of sodium hydrate, 151 ; hybridization experiments, 261.

Archenteron, of Echinoderms, 3, 185; in lithium larvae, 137; of Amniota, 8; in I-Iemigastrula, 159; everted, sec Exogastrula; in double monsters of Frog, 172; tip of, removed, 195 ; of partial larvae, 198, 205, 221.

Architecture of nucleus in Mosaic Theory, 19.

Area vasculosa, 110.

Arenicola, segmentation of, 26, 30, 47 ; effect of ions on larvae, 135. Arm, rate of growth of, 70; varia bility, 74; of Pluteus, see Pluteus.

Arrangement of systems of drops or bubbles, 43, 44.

Arrest of development at low temperatures, 97, 99, 102, 104.

Arrhenokaryotic, 267.

Arthropods, blastoderm of, 5, 114; muscles of, 5 ; somites of, 11 ; nerve-ganglia of, 11 ; segmentation of, 24.

Artificial parthenogenesis, see Parthenogenesis.

Ascaria lumbricoides, 258.

Ascaris me-galocephala, segmentation of, 27, 28, 34, 47; cell-movement, 29; simultaneous division of related cells, 31 ; eggs poisoned by oxygen, 112 ; fusion of eggs to form double monsters, 202; symmetry of egg

SUBJECTS 323

and embryo, 245; diminution of chromosomes, 252, 253, 256-258; individuality of chromosomes, 256; dispermy, 257.

Ascaris nigrorenosa, 33, 34.

Ascidians, segmentation of, 24, 26, 47, 54, 229,235 ; efi'ect of solutions, 140; isolated blastomeres, 230, 237 ; symmetry of egg and that of embryo, 229, 235, 245.

Ascidiella, egg- and embryonic axes, isolated blastomeres, 229, 230.

Asplanchna, unequal asters, fertilization spindle, 34, 48.

Asters, spiral, 40; unequal, 80; induced by salts, 124, 125; altered by alkaloids, 128-130.

Aster-ias, flattening of blastomeres, 45; artificial parthenogenesis, 108 ; effect of atropine, 131 ; exogastrulae, 140 ; necessity of sulphate, 144; necessity of potassium, 146; blastomeres without magnesium fall apart, 148; blastula cut up, 194; tip of archenteron removed, 195 ; coelom-sacs removed, 195 ; ochracea, heterogeneous cross-fertilization, 262.

Asteroids, segmentation of, 24, 26, 28, 47, 64.

Atmospheric pressure as affecting growth, 2; reduced, 109, 110; increased, 114.

Atrium, 229.

Atropine, 131.

Attachment of cells to other bodies, 5.

Auditory vesicle of Vertebrates, 6.

Axes of embryo, see Embryonic axes.

Axial organs, correlations between, 75.

Axis cylinder, 273.

Axis of eg, see Egg axis.

Axolotl, 119.

30;

Bacterial toxines, 132.

Barium, 150.

Bases, 122.

Ba/tmchus, 178.

Beginnings, knowledge of, 289, 298.

Belgians, growth of, 63.

Benzole, 42.

B6759, pressure experiment, 39; isolated blastomeres and egg-fragments, 209-211.

Bilateral egmentation, see Segmentation.

Bilateral symmetry, see Symmetry.

Bile-capillaries, 6.

Bipinnaria, necessity of sulphate, 144.

Y2 324

Birds’ eggs, effect of electric current on 91.

Blastema, metanephric, soc Kidney.

Blastococl, see Segmentation cavity.

Blastocyst of Mammalia, 2, 6, 7, 115.

Blastoderm, of Arthropods, 5, 114, 273 ; of Cephalopods, 6 ; of Sauropsida, 6; growth of, without formation of primitive streak, 104; growth of oxygenotropic, 114, 273 ; isotropic, in Teleostei, 179.

Blastomeres, separate, in Triclads and Salps, 5; in Oceania, 181 ; grouping of, in Salps, 11 ; size of, 29 ; separation of, 45; before division, 45; in calcium-free sea-water, 45, 150; without magnesium, 148 ; flattened against one another, 45, 53 ; movements of, 29, 42, 53.

— ‘isolated’ development of, in the Frog, 159-161, l69—l71,173 ; in the Newt, 173 ; in Fishes, 178 ; in Amphioxus, 179, 180; in Coelenterata, 181, 182; in Echinoderms, 190 sqq.; in Nemertines, 204, 205 ; in Ctenophora, 209-211 ; in Mollusca, 215 sqq. ; in Ascidia, 229, 230, 237, 239 ; reason for difierences in behaviour of, 241-244.

Blastopore, dorsal lip of, in Frog, 80; in forcibly inverted eggs, 82, 84; rim of, thickened by heat, 99 ; fails to close, 99, 119 sqq., 133; in half-blastomere of Frog, 170; in double monsters of Frog, 172; injury to lip of, in Fishes, 178; in Ascidia, 235; in Molluscs and Annelids, 244.

Blastula, of Echinoderms, 2, 6, 115, 185 ; in lithium salts, 137 ; opaque, without potassium, 146 ; opaque, in neutral media, 150; crumpled, without carbonate, 148 ; of Coelenterates, 6 ; of Sponges, 6 ; pieces of, in Siphonophora, 181 ; in Echinoids, 194 ; in Nemertines, 206 ; long-ciliated, from animal cells of Echinoids, 192; united to form one embryo, 201, 202.

Bleu de Lyon, 94, 96.

Blood,the first to be formed (Harvey), 14.

Blood-vessels, growth of, 5; branching of, 6 ; lumen of, 11 ; distended at low temperatures, 104 ; muscles of, 278.

Blue light, 94-96.

Balina, 210.

Bombinator igneus, Pflilger’s experiments on eggs, 82, 88.

INDEX OF SUBJECTS

Bone, 2 ; and tendon, 5.

Bonnetty machine, 91.

Boston school-children, growth of, 63.

Boys, sea Human being.

Brachystola, 256.

Brain remains open solutions, 119 sqq.

Branchipus, 22, 24, 47.

British Periwinkles, 71.

Bromides, 128, 132,133, 134.

Bromine, 141, 145.

Budding, a form of development, 1 ; nucleus in, 284, 285.

Buds of Doliolidae, 5; of plants, 11 ; of Vertebrate limbs, 11.

Bu,/‘o, absorption of water by tadpoles, 58; acclimatization to heat, 100; rate of growth affected by temperature, l02 ; effect of solutions, 120.

Butyrate of sodium, 140.

in certain

Caesinm, 146.

Caffein, 120.

Calcium, efl‘ect of absence of, 45, 148 ; effect on cilia and muscles, 135, 150; acetate, 49; phosphate, 58, 149; chloride, 123, 133; nitrate, 135; hydrogen phosphate, 148, 150; carbonate, 148, 150; seawater without, for isolating blastemeres, 45, 150, 190.

Callidina, 34.

Cane-sugar, effect of, on Frog's eggs, 120, 121, 133, 185, 136; artificial parthenogenesis, 123.

Capillaries, 5; anastomoses of, 6; absence of, without oxygen, 110. Capillarity, in cell-division, 41 sqq.,

145.

Cupitellu, 26.

Carbon dioxide, fatal to Frog‘s eggs, 110; to Teleestean ova, 111; to Echinoid eggs, 112 ; not fatal to Ascaris eggs, 112; quantitative determination of, 112 ; excess pro~ duced by Chick in pure oxygen, 112; neutralized by hydroxyl, 151.

Carbonate, necessity of, 148-150.

Carbon-ion, see Carbonate.

Carcinus mocnas, growth-rate, 71 ; decrease of variability, 72, 74.

Cardinal temperature points, sec Temperature.

Cartilage, 2.

Catamenia, 294.

Cation, 136, 145.

Causal, see Cause; causal harmony, 284, 285, 292.

Cause, explanation in terms of cause and eifect, 12, 20, 286-289, 290, 292, INDEX OF SUBJECTS

296, 297, 298; formal, 13, 293, 296 ; eillcient, 13, 296, 297, 299; final, 20, 296, 297, 299.; material, 294, 296, 299.

Cavities, development of, 11.

Cavity perivitelline, 79 ; and sagittal plane in Frog, 165-168; segmentation, see Segmentation cavity.

Cell~plate, 41.

Cells, animal and vegetative. differences in potentiality, 191, 204206, 242.

—— division of (see also Segmentation), a factor in development, 2, 22 sq.; not necessarily a process of differentiation, 22, 166, 245, 246, 279; meridional, 22, 32; in ‘compressed eggs, 34, 36; equatorial, 22; latitudinal, 22, 32; in compressed egg, 34, 36; dexiotropic, 26, 28; laeotropic, 26, 28; alternation of direction of, 25, 28; direction of, 29, 54; depends on that of nucleus, 31, 48, 55; pressure experiments on, 34-39; and yolk, 24, 29, 48; and surface-tension, 41 sqq.; influence of gravity on, 78 ; influence of electricity on, 93 ; unequal, 29, 30, 168; rate of, 29, 261; suppressed, 55, 56, 106, 117; simultaneous division of the ovum into several cells, 55, 56, 118, 128, 130, 264, 265; in plant-cells, 41; qualitatively unlike, 158, 286; power of, restored in fertilization, 252.

— follicle, of Tunicatn, 5; and cell aggregates, movements of (Davenport), 4 sqq. ; movements of, in sogmentation, 29, 42, 222; number of, in partial embryos or larvae: in the Newt, 173; in Amphiorcus, 181; in Coelenterata, 182; in Echinoids, 197, 269; in Nemertines, 206; separation of, 45, 105, 145.

Cellulation, 162.

Cellulose, 58.

Centrifugalized eggs, 29, 87, 88.

Centrosomes, heterodynamic, 30 ; in artificial parthenogenesis, 124,125; direction of division, 40; division prevented, 265, 267.

Cephalopods, blastoderm of, 6; segmentation of, 27 ; symmetry of egg and axes of embryo, 245.

Cerebratulus, isolated blastomeres and egg-fragments, 204-208.

Cestoda, 28.

Cctochilus, 22.

Chaetopods, artificial pertinenc 325

genesis, 124; pressure experiments, 39, 213.

Ghaetopterus, 214. .

Chemical agents, effect of various, 126 sqq. ; need of, 142-152.

Chemically equivalent solutions, 140.

Chemotactic, 55, 273.

Chest-girth, change in rate of increase of, 70.

Chick, Harvey, 14; Malpighi, 15; do Buifon, 15 ; percentage of water in, 59, 60 ; decline of growthrate, 67; effect of electric current, 91 ; influence of light of various colours, 96 ; respiration of, 109, 110, 113; effects of heat and cold, 102-105 ; efiects of poisons, 132.

Chloral hydrate, effect on fertilization, 128-130.

Chlorates, 145.

Chlorides, 123, 133; see also Sodium chloride, and Chlorine.

Chlorine, necessity of, 145.

Chloroform, 42; and vitelline membrane, 129.

Chondrin, 58.

Chorion, of Teleostei, 35.

Choroid, 273; choroid fissure, 273.

Chorophilus, 120 ; acclimatized to salt, 136.

Chromatin, the vehicle of inheritance, 252; individuality of, 256,

265,266. Chromosomes, number of, varied artificially, 267; in merogony,

267; in artificial parthenogenesis, 125, 267; and cell-volume, 268; and size of nucleus, 268; and number of cells, 268; irregular distribution of, in poisoned eggs, 128-130; in dispermic eggs, 253, 265; individuality of, 252, 256; diminution of, 252, 256-258.

Cilia, apical tuft of, in Plutei. without sulphate, l44; in Pilidium, 204-206.

—' movement of, 135; independent of sulphates, 144; without magnesium, 147 ; in neutral media, 151.

Ciliated ring of Pluteus, without sulphate, 144; without calciumcarbonate, 148; of Mollusca and Polychaeta, 213, 220.

Cirrhipedes, segmentation of, 22, 24 ; fertilization and egg-structure, 250.

Olausilia, decrease of variability, 74.

Cleavage, see Segmentation.

Clepsine, germ-bands of, 6; rings, 251.

Clove-oil, 54.

pola r326 INDEX OF

Clymanella, 46.

Clytia, 181.

Coca(i)n, effect on fertilization, 12818 .

Coefilcient of growth, 65; of variability, 7l, 72, 78; of correlation, 75.

Coelenterata, skeleton in, 2; unipolar immigration in, 11 ; segmentation of, 22, 28, 47, 54; development, of isolated blastomeres, 181.

Coelom, of Echinoderms, 8; of Annelids, 6; epithelium of, and gonads, 7; lumen of, 11; sacs removed, 195.

Cohesion of blastomeres, 45, 148, 150.

Cold, effects of, on segmentation and development, 99 sqq.; on fertilization, l07, 108; arrest of development due to, 97, 99, 102, 104; together with potassium cyanide, 132; produces artificial parthenogenesis, 108, 124; segmentation of an isolated blastomere becomes total, 216.

Combination of original elements, 286.

Composition, organs formed by, 3, 277, 285.

Concentration of material of blasteporic lip in axis of embryo, 178; of sea-water, 124.

Concrescence of lips of blastopore, 178; of layers, sea Cells, movements of.

Conditions of development, see Development.

Cone of entrance, 128.

Connective tissue, 273.

Consciousness, of the process, in development, 20, 291, 297.

Constriction, see Cells, movements of.

Contact stimuli, 137, 272, 275-277.

Contractility of cytoplasm, 130, 131.

Contraction of muscles, inhibited by magnesium, 135, 148 ; sodium necessary for, 135, 145 ; potassium necessary for, 147.

Co-ordination, 284.

Copper sulphate, 96.

Cornea, causes of formation, 275, 276.

Corpus luteum, 5.

Corpuscles, concentric, of thymus, ll.

Correlation, 75; decrease in, 75, 277; between symmetry plane, first furrow and sagittal plane, 167.

Cosmic process, 298.

Costae of Ctenophora, 211, 212.

SUBJECTS

Cotylorhiza, necessity of potassium, 146.

Crab, see Carcinufi

Cramgon, 24.

Gnepidula, segmentation of, 26, 30 ; asters and protoplasmicmovement, 40; flattening of blastomores, 45; parallel polar furrows, 46.

Crescent, gray, see Gray crescent.

Crinoids, 22.

Cross-fertilization, see Hybrid.

Cross furrow, sec Polar furrow.

Crustacea, segmentation of, 22, 24, 47; eggs of, and gravity, 78; structure of egg, and embryonic axes, 245.

Orystallodes, 18].

Ctenolabrus, cell-division suppressed, 56, ill; first furrow and sagittal plane, 178 ; need of oxygen for, 111, 262.

Ctenophora, segmentation of, 26, 208; micromeres, 30; pressure, 39; influence of gravity on eggs, 78; micromercs displaced, 211 ; isolated blastomeres, 209, 210; cg,-;—frug~ ments, 212; effect of fertilization, 250.

Gyclas, 26.

Cyclops, 22.

Cynthia, development, 230; isolated blastomeres, 237 ; symmetry of egg, 232, 250.

Cytarme, 45, 53.

Cytastors, 125.

Cytochorismus, 45.

Cytolisthesis, 53.

Cytoplasm, organ-forming substances in the, 19, 208, 212, 213, 217, 224, 225, 228, 233, 236, 240, 241, 246, 280, 286.

-—nucleus and, 31, 131; ratio between, 65, 269; inter actions of, 266, 283, 284.

-— increase of, in differentiation, 65, 66 ; ascent of, in inverted eggs, 84 ; receptive to stimuli, 283; paralysed by poisons, 127; contractility of, 130, 131; determines diminution of chromosomes, 257.

Cytotaxis, 55.

Cytotropism, 55, 273.

Daphnella, 24.

D_aphm'a, 24.

Darkness, Fundulus embryos, 94 ; tadpoles of Frog, 95 ; eggs of Limmwa, 95 ; Echinoid larvae, 96.

Death-rate, selective, 74 ; in various lights, 94-96; in desiccators, 115; of heterogeneous hybrids, 262. INDEX OF SUBJECTS

Decay, senile, 65. , Decapoda, segmentation of, 24. Decline of growth-rate, 61-71. Decomposition, tension, 135. Defects, local, due to local injuries, 17, 159.

Degeneration, gray, of medullary groove, 119, 135.

Dehydration, see Water, withdrawal of.

Dendritic figure, 130.

Dentalium, development, 222-224 ; removal of polar lobe, 224; isolated blastomeres, 225, 226 ; egg-fragments, 226.

Dependent differentiation, see Differentiation.

Descemet's‘ membrane, 276.

Desiccation of Hen‘s egg, 115; of Frog’s egg, 123.

Detachment of parts, 8.

Determinant judgement, 287, 288.

Deutoplasm, see Yolk.

Development, defined, 1 ; component factors of, 2; specific, 1, 15, 17, 280 ; and inheritance, 1 ; rhythm of, 3 ; external conditions of, 18, 20, 152, 155-157; a predetermined process, 19; internal conditions of, 20, 158 sqq., 279286; rate of, influenced by temperature, 100, lol ; without potassium, 146, 147; mgnesium, 148; and calcium, 150; in partial larvae, 200, 204; acceleratcdhsea Acceleration ; retarded, see Retardation ; arrested, see Arrest ; suspended, see Suspension.

Deviation, standard, 71.

Dexiotropic division, see Cell.

Dextrose, Frog's egg, 121 ; Hen's egg, 132.

Dicephalus tetrabrachius, 175.

Dicyemidae, 11.

Differentiation, see also Cytoplasm and Nucleus; defined, 2; histological, 3; self-differentiation, 17, 18, 158, 240, 286; increase of, 76, 176, 277, 284 ; dependent, 18, 158, 162, 277, 286; progressive, 247; and cell-division, 22, 166, 213, 236, 245, 246, 279; and growth, 62, 65, 279; and increase of cytoplasm, 65 ; cytoplasm in, 19, 208, 212, 213, 217, 225, 227, 237, 240, 241, 246, 261, 266; nucleus in, 251 sqq.; interactions of the parts in, 271277.

Dilution of sea-water, as a means of preventing cell-division, 55; ex 327

ovates produced by, 118, 189, 190, 194; causes irregular segmentation, 118, 187, 194.

Dimensions, see Size.

Diminution of chromosomes, 252, 256-258.

Diphtheria toxine, 132.

Diplogasler, rotation of fertilization spindle, 34; egg- and embryonic axes, 250.

Diplokaryotic, 267.

Diprosopus triophthalmus, 175.

Directive stimuli, 162, 272.

Discocelis, segmentation of, 25, 80, 47; crossed polar furrows, 46; fertilization and egg-structure, 250.

Disintegration of epithelium, 119, 120, 135.

Dispermy, in Ascaris, 257; in Echinoids, 263--265.

Dispersion of cells, 11.

Division of nucleus and cell a factor in development, 2; of nucleus, sea Nucleus; of cell, sea Coll; of oildrops, sec Oil-drops; of centrosomes, see Centrosomes.

Doliolidae, buds of, 5.

Dorsal lip of blastoporc, sec Blastepore.

Double monsters, see Monsters.

Dreissensia, 45, 47.

Drops of fluid, 42, 43; of oil, 43, 49 sqq.

Duck embryos, decline of variability in 71.

Ducts, see Gland, Segmental; lumen of, 11.

Duplicitas anterior, 175.

Dytiscus, 258.

Earth-worm, ectoderm of, 3; nephridia, 5.

Echinoderm, blastula, 2, 110, 185; spicules of larva, 2; archenteron divides into gut and coelom, 3; mesenchyme, 5; gastrula, 5; segmentation of, 22, 24, 26-28, 54, 188 ; pressure experiments on eggs, 39, 185, 186; influence of gravity on eggs, 76; artificial parthenogenesis, 123 ; eifects of sodium, potassium, lithium, on larvae, 137-140 ; blastomeres disarranged, 187 ; blastomeres isolated, 190 sqq.; blastulae and gastrulae cut up, 195; egg-fragments, 195-197; one embryo from two blastulae, 201, 202; number of cells, rate of development and, size of partial larvae and their organs, 198-200. 328

Echinoids, egg, segmentation of, 22, 27 ; position of nucleus in egg, 81 ; normal development of, 183-185; pressure experiments on, 37, 88, 185, 186 ; blastomeres disai-ranged, 187, 194; isolated blastomeres, 190 sqq. ; egg-fragments, 195-197; fragments of blastulae and gastrulae, 199, 195; one embryo from two blastulae, 201, 202; larvae, influence of light on, 95. 96 ; require oxygen, 112; spicule cells in, 114; influence of potassium, sodium, and lithium, 137-140; partial larvae, size of, rate of development of, number of cells of, 198-200; hybrids, 258-262.

Echinus, pressure experiments, 37, 38, 185, 186; suppression of celldivision, 55; influence of light, 94; ciliary movement in larva, 135; potassium, sodium, and lithium larvae, 137; necessity of certain elements for, 142 sqq.; blastomeres disarranged, 187, 188, 194; blastomeres isolated, 190 sqq.; segmentation of egg-frag ments, 195-197; blastula cut up, 194; grafting of blastula fragments, 202 ; size of partial larvae, 199, 201; hybridization experiments, 258-262 ; number of chromosomes varied, 267.

Ectoderm, of Earthworm, 3; growth of, in Amphioacus and Vertebrates, over medullary plate, 9; of Simmculus, 9 ; of lithium larvae, reduced, 139, 140; of Echinoid, gastrula, separated,I95 ; ofpartial larvae,198.

Ectoproctous Polyzoa, segmentation of, 22.

Elficient cause, see Cause.

Egg axis, how determined, 79, 163, 183, 204, 208, 232, 249, 250, 280; and gravity, 78; and embryonic axes, 81, 165, .166, 174, 204, 209, 229, 238, 236, 244, 281; and segmentation furrows, 81, 85, 229, 235; secondary, in inverted eggs, 85.

Egg-fragments, enucleate, fertilized, sea Merogony; segmentation of, see Segmentation.

Elasmobranchs, lower layer cells, 5 ; segmental duet, splitting of, 6 ; yolk-nuclei, 88; injuries to germring. 178.

Elastic plates and tubes, layers of Chick compared to, by His, 3.

Electricity, 91 sqq.

INDEX OF SUBJECTS

Elementary organs, see Organs.

Emboitement, 14.

Embryology, experimental, 1, 18; descriptive. 12; comparative, 12, 16 ; aims of, 13, 156, 157, 297, 298.

Embryonic axes, and gravity, 78; and symmetry of egg, 8], 165, 166, 174, 204, 209, 229, 233, 236, 244, 266, 281 ; influence of light on, 93.

Embryonic plate, of Mammals, 9.

Embryos, double, 201, 202; partial, see Blastomeres, isolated, and Eggfragments.

End, knowledge of the, 286, 289, 296, 297, 299.

Endoderm of Echinoid larvae, separated, 195.

End—organ and nerve, see Nerve.

Energy, life not a form of, 291.

English, growth of, 63.

Entelechy, 291, 297.

Environment, physical and chemical, adaptation of developing organism to, 157.

Epidermis of Earthworm, 3.

Epigenesis (Harvey), 13, 15; (Wolff), 16; not a theory, 17, 19.

Epithelium, degeneration of, 120.

Equatorial division, 24.

Equilibrium, osmotic, 118.

Equimolecular solutions, 140.

Equipotential, 176, 277.

Essential oils, 132.

Ether, 132.

Ethical, 289.

Eucharis, 209.

Evaginations, see Cells, movements of.

Eversion of gut, see Exogastrula.

Evil, problem of, 299.

Evolution, theory of (of the individual), 14 ; modern form of, 19, 158 ; (of the race), 16.

Excretory, see Kidney.

Exocoefus, 178.

Exogastrula, in lithium salts, 137; without sulphate, 143; of Ascitlitt, 237.

Ex-ovates, of A rbacia, 118.

Experimental method inembryology, 1, 13, 297, 298.

External conditions of development, see Development.

Eyes, width of face between, growth of, 70.

Fat, 58. 1

Fate a function of position, 188.

Ferments, in nucleus, 288.

Fertilization in Ascaria nigrorenosa, 38; altered by heat, 107, 108; INDEX OF SUBJECTS

altered by alkaloids, 126 sqq. ; independent of sulphates, 144; without potassium, 146; without magnesium, 147 ; in neutral media, 151 ; alteration of egg structure in, 80, 163, 222, 232, 247251 ; two processes involved in,252.

Film, at surface of blastomeres, 45, 64, 150; of drops of fluid, 42, 45, 54.

Final cause, sea Cause.

First furrow, coincidence of, with sagittal plane, see Furrow, first.

Fissure, choroid, 273.

Flattening of blastomeres against one another, 45, 53.

Flexure, cranial, 110.

Folds, medullary, see Medullary.

Follicle cells, in Tunicata, 5.

Follicles, of hair, 7.

Food, growth dependent on, 2, 58, 59.

Foot, rate of growth, 70. Form, production of, 1 ; nucleus necessary for, 252, 254.

Formal cause, sec Cause.

Formate of sodium, 145.

Formative stimuli, 273. Fovoa germinativa, 79.

Fragments of egg, sec Egg-fragments ; of hlastulae, and gastrulae, see Blastulae, Gastrulae.

Framboisia, 135.

Freedom, 289, 299.

Fresh water, Funduluseggs in, 117,136.

Frog, ovarian and uterine egg, 79; efiect of fertilization, 163; eggs forcibly inverted, 18, 78,158; influence of gravity upon. 18, 78 sqq. ; eggs placed on vertical wheel, 85 ; eggs kept in constant motion, 86 ; egg centrifugalized, 29, 87, 88 ; pressure experiments, 34-37, 40, 168; absorption of water by tadpoles, 58; eggs exposed to electric currents, 92, 93; eggs, influence of light on, 94 ; eggs, influence of heat on, 97-99; of cold on, 99-100; eggs, respiration of, 110-112; effect of sodium chloride on eggs, 119, 120, 276 ; of other substances, 120, 121 ; acclimatizod to sodium chloride, 136 ; first furrow and sagittal plane, 17, 159, 165-168; half—embryo from half-blastomere, 18, 159 sqq., 169-171 ; double monsters, 171, 172; development of animal and vegetative blastomeres, 173 ; formation of lens,275,276 ; of cornea, 276, 277.

Frontal breadth in Carcinus, growth of, 71 ; variability of, 72.

329

Fuchsin, 94.

Functional adaptation, 290.

Fundulus embryos, in light and darkness, 94 ; need of oxygen for, 111, 114, 274 ; in fresh water, 117 ; eifect of ions on, 135, 136; in sodium chloride, 117; in magnesium chloride, 276; first furrow and sagittal plane, 178; injuries to blastopore, 178.

Furrow, first, and sagittal plane in Frog, 17, 159, 165-168 ; in Necturus, 168; in Newt, 175; in Fishes, 178; in Ascidia; 229, 233, 235 ; in Echinoids, 250 ; and plane of symmetry, 167, 233; and horizontal plane in Newt, 175 ; first and entrance point of spermatozoon, 40 ; in Frog, 247, 248; in Toazopneustes, 250.

Furrows, polar, parallel, and crossed, 25, 26, 46,47; in Roma, 53 ; in systems of oil drops, 50.

Fusion of cell-aggregates, see Cells, movements of; of larvae to form double monsters, 137, 201 ; or one larva, 202.

Gulvanotaxis, 272.

Galvanotropism, 272.

Gammams, 24.

Ganglia, see Nerve.

Ganoids, 26.

Gastrula, of Echinoderms, 5; opaque in neutral media, 151 ; of animal and vegetative cells, 191194; pieces of, in Echinoids, 194 ; of Ascidia divided, 238.

Gastrula wall of lithium larvae, 138-140.

Gastrulation, need of sodium for, 145 ; of isolated blastomeres, 191-194.

Gemmule of Sponges, 5, 11.

Genetic restriction, 246, 277; see also Potentialities, limitation of.

Geophilus, 4.

Geotropism, 272.

Germ-bands, 5; of Clcpsim-, 6; from teloblasts, 29 ; of Crustacea, 34. Germ-cells, liberation of, 11 ; the vehicles of inheritance, 1, 252; of

Ascaris, 253.

Germ-layers, 2.

Germ-ring, injuries to, 178.

Germinal localization, His's principle of, 17.

Germinal value, and loss of potentiality, 181; and number of cells, 182, 197, 206, 269; and size of 330

larvae, 198, 199, 269; and rate of development, 200, 204.

Geryonia, 181.

Gill slits, abnormal, 104.

Girls, see Human being.

Glands, growth of necks of, 5, 273; branching of, 6; club-shaped, of Amphfoxus, 6.

Globules, of Wolff, 16.

Glycerine, 132.

Gonads, from coelomic epithelium, 6.

Grafting of pieces of blastulae, 202.

Gravity, influence on segmentation of Frog's egg, 18, -78, 158; influence on development in general, 78 ; Plliiger’s views, 83 ; directive influence of, experimentally eliminated, 85 ; replaceable by a contrifugal force, 87; eifect on Anfennu(aria, 272, 273; on Serlzdaria, 272.

Gray crescent of Frog's egg, 80; said to be due to gravity, 87; caused by spermatozoon, 247, 248.

Gray degeneration, see Degeneration.

Gray patch in inverted eggs, 85, 87.

Green light, 94-96.

Growth, a factor in development, 1, 279; conditions of, 1, 58, 59; local inequalities of, 2, 3, 11; in length, 5; of spherical and plane surfaces, 6; defined, 58; without differentiation, l04; dependent on absorption of water, 58, 59, 68, 115, 116,146; and other substances, 58 ; change of rate, 61-71; change of variability during, 71-75; change in correlations during, 75, 76; rate of, defined, 60 ; variable, 74; influenced by temperature, 101.

Guinea-pig, change of rate of growth, post-natal, 61, 62, 65; pre-natal, 62; decline of variability in, 71.

Gut, muscles oh 5 ; of Echinoderms, 3; imaginal, of Insecta, 5; of Pluteus, in potassium, 137 ; without sulphate, 143; without magnesium, 147 ; without potassium, 146.

Haemoglobin, not formed in absence of oxygen, 110.

Haemorrhage, due to cooling, 104.

Hair, follicles, 7.

Half-embryo, depends on position of egg, 170, 171.

Hand, rate of growth, 70; variability, 74. Harmony, causal, 284, 285, 292; of composition, 285.

Head, length, rate of growth, 70;

INDEX OF SUBJECTS

variability, 74; correlations with other parts, 75; breadth, rate of growth, 70; variability, 74; correlations with other parts, 75.

Heart, the first organ to be formed, according to Aristotle, 13, 294; -beat of Chick at low temperatures, 104; halves of, remain apart, 104; distended, 104; beat of Fundulus in hypertonic solution, 117.

Heat, 97 sqq., as affecting growth, 59; effect of, on Frogs’ eggs and embryos, 97-99; acclimatlzation to, 100; effect on Sphaerechinus ova, 105, 106, 187; on fertilization, 107, 108 ; stimuli, 272.

Heliotropism, 272.

Hemiblastula, 159; superior, 161.

Hemicrania, 119.

Hemi-embryo laternlis, anterior, 161.

Hemigastrula, 159.

Hemikaryotic, 267.

Hemimorula, 159.

Hemitheria anteriora, 18.

Hen’s egg, axis vertical,‘-78 ; need for being turned, 89; exposed to shocks, 89; perpetually rotated, 90; exposed to sound-vibrations, 90 ; placed between poles of a magnot, 91 ; influence of light on, 93, 91; loss of weight of, 115; effect of poisons on, 132.

Heterocentron, 58.

Heterodynamic centrosomes, 30. _

Heterogeneity of ovum, 2, 157; and homogeneity, 298.

Heterogeneous hybridization, 262.

Hips, rate of growth, 70. Holoontoblastia, 139.

Holothurians, segmentation of, 22.

Homologies, sought for in descriptive embryology, 12.

Human being, decline of growth—rate after birth, 63, 64, 65 ; before birth (rte Human embryo) ; rise of growth-rate at puberty, 65 ; decline of variability, 73; increase at puberty, 73; decline of correlations, 75. ‘

Human embryo, percentage of water in, 59, 60; decline of growth-rate, in weight, 63; in stature, 68; of organs, 70.

Humid atmosphere, necessary for Hen’s egg, 115.

Hybrid Pluteus from enucleate eggfragment, 253, 258-260; Plutei, various, 262; heterogeneous, 262.

Hz/dractinia, 47.

159, 171 ; INDEX OF

Hydranth, see Hydroids.

Hydrochlorate of morphine, 128-180.

Hydrogen, effect of, 109-111, 132.

Hydroids, growth of tolons and bydranths, 5 ; attachment of, 272 ; from isolated blastomeres, 181.

Hydroxyl, 150, 151.

Hyoid of tadpoles, enlarged, 114.

Hypertonic solutions, see Osmotic pressure.

Hypotonic solutions, pressure.

see Osmotic

Idioehromatin, 258.

Idioplasm, 159.

Idioplasma, in the nucleus, 19.

Ilyamassa, segmentation, 26, 214, 215; isolated blastomeres, 215-217 ; removal of polar lobe, 217.

Immigration, see Cells, movements 0 1

Immunity, 290.

Increase of mass, 58, 115; of selfdifferentiation, 75, 176, 277, 284; of structure, 2, 279.

Increments, percentage of growth, 60.

Index, mitotic, 65; of development, 103.

Individuality of chromosomes and chromatin, 252, 256, 265, 266.

Induction, 282, 283.

Inequalities, local, of growth, see Growth.

Inequipotential, 176, 277.

Inheritable qualities, represented by units in the germ, 19, 159, 246, 247, 279, 280.

Inheritance, material basis of. 1, 19, 252; Aristotelian explanation of, 294 ; mechanism of, 1, 19, 280.

Injuries, local, the cause of local defects, 17, 159.

Insects, gut of, 5; pupae, phagocytosis in, 5; segmentation of, 24; polar nuclei, 29 ; eggs of, and gravity, 78 ; symmetry of egg and embryo, 245.

Insemination, first elfoct of, in Frog, 79.

Insufficiency of material, sec Potentialities, limitation of.

Ingeractions of the parts, 271-277,

84.

Internal conditions of development, see Development.

Interruptions of continuity, see Cells, movements of.

Invaginations, see Cells, movements of.

SUBJECTS 331

Investment by cells, see Cells, movements of.

Iodides, 183.

Iodine, 141, 145.

Ion-proteids, 136.

Ions, 135, 186, 140.

Iris, 276.

Iron, 141.

Irregular distribution of chromosomes, see Chromosomes.

Irregularities of segmentation, see Segmentation.

lschnocliilon, 25, 46.

Isobilateral segmentation, see Segmentation.

Isopoda, 24. '

Isotonic solutions, 120, 123, 124, 140, 142.

Isotropy of egg, 18, 158, 202, 280; of blastoderm, 179.

J elly of Frog’s spawn, 42, 43, 79. Judgement, Kritik of Tcleological, 286-289.

Karyokinesis,without calcium, 150 ; significance of, 252.

Karyokinetic plane, 185.

Kidney, larval, of Lamellibranchs, 5 ; tubules, branching of, 6; anestomoses of, 6; tubules (mesonephric).fusionwithvasaefferentia, 6; tubules in metanephric blastema, ll.

Labrax, 145.

Lacertilia,inner wall of pineal vesicle, 9.

Laeotropic division, see Cell-division.

Lamellae, systems of, 41 sqq.

Lamellibranchs, larval kidney of, 5.

Laodice, 181. ,

Lappets of Pilidium, 204, 207.

Larva, of Sponges, 6; of Dicyemidae, 11; of Coelentcrates, 6 ; characters of, developed early, 3; partial, see Blastomeres, isolated, and Egg-fragments.

Latitudinal division, 22, 24, see also Cell-division.

Law, Biogenetic, 12, 16; of alternation of direction of cleavage in ‘spiral’ eggs, 25; Sachs’, 28, 40; Weber's, 272.

Laws of causation, 13, 285, 298.

Leg, rate of growth of, 70.

Lens, outer layerof, 7 ; absent, in certain solutions, 134; causes of formation, 275, 276. 332

Lepidonotus, 25, 46.

Lepidosteus, 26.

Light, general effect on developing organisms, 93 ; on fern prothallus, 272; on Serpula, Sormlarella, 272; effect on direction of embryonic axes, 93 ; of various colours on eggs of Echinus, Planarbis, 94 ; Rana, 94, 95 ; Trout, 95 ; Limnaea, 95; Echinoid larvae, 96 ; promotes oxidation, 112.

Limax, segmentation of, 25, 26, 30; spiral asters, 40.

Limbs, buds of, in Vertebrates, ll.

Limitation of potentialities, see Potentialities.

Limnaea, 67.

Linear cell aggregates, 5.

Liriope, 181.

Lithium chloride, eggs of Amphibia, 120, 135; salts, on Amphibian eggs, 120, 138, 135; on Echinoid larvae, 137-140, 146.

Liltorina, 71, 72, 74.

Lobe, polar, 214, 228; removal of, 217, 224, 227.

Localization of ontogenetic effects, 289.

Loss of potentialities, soc Potentialities.

Lucifer, 22, 47.

Macromercs of Echinoids, 22, 30, 185, 192; of Ctenophora, 211; of Mollusca, 215, 221.

Magnesium in artificial parthenogenesis, 123; Frog embryos, 133, 135; Fundulus, 135, 276; Arenicola larvae, 135; effect on ciliary and muscularmovement, 135; necessity of, 147.

Magnetism, 91 sqq.

Male element, function of, according to Aristotle, 13.

Mammalia, blastocyst, 2, 6. 7, 115; truncus arteriosus, splitting of, 6 ; trophoblast of placenta, 7 ; embryonic plate, 9 ; segmentation in, 24.

Man, see Human being.

Massive cell aggregates, 11.

Material basis of inheritance, 1, 19, 252; cause, see Cause ; explanations of ontogeny, 12, 20, 286-289, 290, 296, 298.

Materialism, 301.

Matter and material cause, 13.

Matter and mind, 801.

Maturation, nuclei of germ-cells in, 252, 254.

INDEX OF SUBJECTS

Maximum temperature, see Temperature.

Mechanical, see Mechanism; Mechanical agitation, 89. Mechanism of inheritance, 1, 280; mechanism, explanation of ontogeny as a, 12, 20, 286-289, 290, 292, 296, 298.

Medulla, roof of, 7; solid, in Frog's embryos grown in certain solutions, 133.

Medullary folds, 9; not formed at low temperatures, 104 ; divided at high temperatures, 99; remain open in various solutions, 119 sqq.; in Hemiembryo, 160.

Medullary plate of Amphioxus, 8.

Mcidusa from isolated blastomere,

81.

Megalecithal eggs, 24.

Membrane of egg, 45, 46; absence, due to poisons, 128; formed by chloroform, 129 ; at surface of cells, see Film ; of shell , 104 ; of Descemet, 276.

Mendelian allelomorphs, 266.

Mercury, 132.

Meridian, streaming, in inverted Frog's eggs, 84.

Meridional division, 22,32; see also Cell-division.

Megridional polarization in Frog's egg,

3.

Meroblastic segmentation, mentation.

Merogony, 131 ; male nucleus only in, 254

Mescnchyme, of Echinoderms, 5; of Echinoids, 185, 26], 262, 269; of partial larvae, 193, 194, 198. 237; of Ascidia, 235 ; of Echinoids, displaced, 274.

Mesoderm, segmentation of, 11 ; in Hemiembryo, 160; deficient, after imury to germ-ring, 179; dependent on presence of polar lobe, 217.

Mesomeres in Echinoids, 27, 185, 192.

Mesonephric tubules, see Kidney.

Migtgibolism, nucleus needful for, 252,

4.

Metamorphosis (Harvey), 14.

Metanephric blastema, see Kidney.

Methods of embryology, descriptive, 12 ; experimental or physiological, 13.

Micromeres in Echinoids, 22, 30, 185, 192; suppressed by pressure, 37, 186; by heat, 186 ; in ‘spiral’ eggs, 25; suppressed by pressure, 39, 213,- rotation of, 29, 47 ; of Mollusca

see SegINDEX OF

isolated, 215, 221 ; of Ctenoplxora, 39, 209-211.

Micropyle, 183.

Migration of cells, 4, 5; of spicule cells in Echinoids, 114.

Mind and matter, 301.

Minimum temperature, see Temperature.

Mitosis,quadripolnr,tripolar,268-265.

Mitotic index, 65.

Mitrocoma, isolated blastomeres, 181 ; fusion of blastulae, 202.

Mbina, 24.

Molecules, meridional rows of, in Frog’s egg, 83.

Mollusca, muscles of, 5; segmentations of, 25; eggs of, influence of gravity on, 78; isolated blastemeres, egg-fragments, 215 sqq.; symmetry of egg and embryo, 244.

Monaster, 267.

Monsters, double, in lithium salts, 138; of Frog, 171, 172; of Newt, 174, 175; of Ampliioxus, 181; of Asterias and Echinus, 194; of Sphaerechiuus, 201.

Monstrosity, 1 ; natural, 18, 159; significance of, 155, 156; produced by shocks, 89; perpetual rotation, 90; by sound vibrations, 90; by electric currents and magnetism, 91 ; by heat and cold, 98 sqq. ; by chemical agents, 120-121, 132; significance for variation, 141.

Moral consciousness, 289, 299, 300.

Morphaesthetic, 291.

Morphine, effect on fertilization, 128130 ; on Hen's egg, 132.

Morphography, 12.

Morphology, method of, 12; experimental, 1.

Mosaik~Theorie, sea Theory, mosaic; segmentation, see Segmentation. Motion imparted by male element,

295, 296.

Mouth, growth of, 70.

Movements, of cells and oell-aggrcgates, 4 sqq., 272 ; in segmentation, seecell;oforgan-formingsubstances, 207, 208, 226, 227; protoplasmic, 40, 41.

Mucin, 58, 79.

Muscles, in Arthropods, 5 ; of Ascidia, 235, 237; in Mollusca, 5; of gut, 5; of blood-vessels, 273; striated, 55; abnormal, in rotated I-Ien’s eggs, 90; contractions of, sec Contraction.

Mutations, 141.

Myotomes, 11.

SUBJECTS 333

Myriapods, 24. Mysis, 24. Myzostoma, 214, 228.

Nature, 801.

Neck, rate of growth, 70.

Necturus, 168.

Nematocysts in Planula, 8.

Nemertines, segmentation in, 25 ; isolated blastomeres and egg-frag ments, 204-208.

Nee-vitalism, 20; see also Vitalism.

Nephelis, 40.

Nephridia of Earthworm, 3, 5: of Annelids, fusion with coelom, 6. Nereis, segmentation in, 25, 47; unequal asters, 80; egg compressed, 39, 213 ; crossed polar furrows, 46; change of shape of cells, 48; arti ficial parthenogenesis, 124.

Nerves, growth 01', 5; branching of, 6; anastomoses of roots, 6; plexuses of, 6; fusion with end-organ, 6; crest, ll; ganglia, fusion of, 11; fibres, 273; physiology of, 290.

Nervous system of Earthworm, 3; oi".l‘eleostei, 6, 11, 133; of Invertebrates, 11 ; of Ascidia, 235, 237.

Neural, sec Nerve.

Newt, development of half-blastomeres, 173; double monsters, 174, 175. .

Nickel nitrate, 94.

Nicotine, and eggs of Bufo, 120; effect on fertilization, 126,130; on Hen’s egg, 132.

Nitrates, 123.

Nitric oxide, eggs of Ascaris in, 112.

Nitrogen, eggs in, 110, 112.

Nomelectrolytes, poisonous effects of, 136 ; see also Cane-sugar, Dextrose, Urea.

Normal temperature, seo'1‘emperature.

Notochord, vacuoles of, 2 ; early differentiation of, 3; application of skeletal cells to, 5, 11 ; formation of in Urodela, &c., 8 ; from archanteron, 11; divided at high temperatures, 99; in cane-sugar, 133 ; whole, in Hemi-embryo, 160; of Ascidia, 285, 287.

Notoehordal tissue, in neural tube and archenteron, 134.

Nucleus, division of, a factor in development, 2, 22 sqq. ; division of, direction determines that of cell, 31, 55; rules of: Hertwig for, 31, 82; rule of Pfliiger for, 82; polar divisions of Insects, 29; polar divisions with equal asters, 81 ; division 334 without cell-division, 55, 56, 118 ; indirect division, see Karyokinesis.

Nucleus, position in cell, 81, 32, 79; injured by poisons, 128-130, 135; of yolk, sea Yolk-nuclei; qualitative division of, 19, 159, 168, 186, 213, 240, 265, 279, 280, 286 ; rapidity of, 65; idioplasm in the nucleus, 19, 159; the vehicle of inheritable characters, 253, 258262; in difierentiation, 251 sqq.; essential for life of cell, 251, 252, 254 ; of germ-cells alike, 252, 254, 256; both male and female, not necessary, 254; decrease in size of, 65; variability in size of, 269; size of, and number of chromosomes, 268; number of, and number of chromosomes, 268; and cytoplasm, ratio between, 65, 269; volume of, and cell-surface, 269 ; responsive to stimuli, 283; reaction of, on cytoplasm, 266, 288, 284.

Number of cells, see Cell; of nuclei, see Nucleus.

Oakland, Mass., growth of, 68.

Obelia, 147, 148.

Obliquity of spindles in ‘spiral ' eggs, 32 ; of egg axis in Rana esculenta.

Occasion, 283.

Oceania, 54.

Oil-drops, 43 ; systems of, 49 sqq.

0ils,essential, 132.

Oniscus, 24.

Ontogeny and phylogeny, 12; causal explanation of, 13, 297, 298.

Operculum of tadpole, not formed after removal of brain, 176.

Opfinglia, artificial parthenogenesis,

4.

Ophiuroids, segmentation in, 24, 26, 28, 47.

Ophryotrocha, 202.

Optic cup, and lens, 134, 275, 276; and cornea, 276, 277.

optic vesicles, absent, 110; injured or removed, 275, 276.

Optimum temperature, see Temperature.

Orchcatia, 24, 26, 28, 47.

Organ-forming substances, see Substances.

Organs, elementary, of first, second, &.c., orders, 3.

Orientation, similar, of egg-particles, 281, 286.

Origin and fate of cells, 246; knowledge of, 288, 298.

school-children,

INDEX OF SUBJECTS

Osmotic pressure, as aflecting growth, 2, 115, 116; as aifeeting celldivision, 56, 117 ; increased by addition of salt, 116, 117 ; the asserted cause of malformations, 120-122; the cause of artificial parthenogenesis, 128, 124 ; decrease of, 118; equilibrium, 118.

Otolith, 239.

Oviduct, in Amphibia and Amniota,9. Oxidation, agents of, 181 ; promoted by light, 112; by alkalinity, 151. Oxygen, lack of, cell-division suppressed, 56, 111, 112 ; effect on pigment of Fundulus, 111, 114; quantitative estimation of amount absorbed, 112; effect of pure, 112 114 ; need of, 109 sqq., 182.

Oxygenotactic, Oxygenotropic, 114, 273, 274.

Oxyhaemoglobin, excess of, in Chick, in pure oxygen, 112.

Papilla, fixing, 229.

Paraderm, of Amniota, 8.

Paramn oil, 49.

Parallelism, psycho-physical, 301.

Paralysis of cytoplasm, 127.

Pars prima genitalia (Harvey), 14.

Parthenogenesis, artificial, produced by mechanical agitation, 90, 124; by cold, 108, 124 ; by increased osmotic pressure, 123, 124; cytology of, 124, 125; maternal nucleus only in, 254; number of chromosomes in, 125.

Patch, gray, in inverted eggs, 85.

Patella, isolated blastomeres of, 218222.

Pelagic ova, 89.

Pellogaster, segmentation, 24.

Penetration by cells, 5.

Peptones, 132.

Percentage increments of growth, 60 sqq. ; of water, 58-60, 115, 116.

Periods, spiral, radial, bilateral, of segmentation, sec Segmentation; variation in, 74.

Peripatus capcnsis, 24.

Perivitelline cavity, 79, 87 ; fluid, 79.

Periwinkle, 71, 72, 74.

Permeability of tissues to salts, &c., 119, 121, 124, 145.

Pegmutation of original elements,

86.

Petromyzon, notoehord in, 8, 183; segmentation, 47 ; artificial parthenogenesis, 124.

Phagocytosis, 5. INDEX OF SUBJECTS

Phallusia, 288.

Pharmacology, 136.

Phuscolosoma, 25.

Phosphorus, effect on Chick, 132; necessity of, 141.

Physa, crossed polar furrows, 46; effect of fertilization, 250.

Physico-chemicalresponsestostimuli, 285. ‘

Physiological zero, see Temperature, minimum.

Physiologically balanced solutions,‘

136.

Physiology of development, physiological laws, 18, 298. Pigment, change of position in isolated blastomeres of Frog, 53; of Frog's egg. 79; disappearance of, in Frog's egg, 80, 163 ; in Fundulus, in darkness, 94; without oxygen, 11], 114; distributed through cell-body (gray degeneration), 135; of secondary mesonchyme in Pluteus, 144; without magnesium, 148; without calcium, 150; in neutral media, 151; of Strongylocentrotus, 183-185; function in gastrulation, 184, 192; of Dontalium, 222; of Cynthia, 230 sqq.,

250.

Pilidium, 205-207.

Pilocarpine, 131.

Pineal vesicles, inner wall of, split in Lacertilia, 9.

Pisces, egg-axis and embryonic axes, 178; half-blastomeres, 178; injuries to lip of blastopore, 178.

Placenta, of Mammals, 7.

Placental Mammals, segmentation, 24.

Plunorbis, segmentation in, 25; crossed polar furrows, 46; light of various colours, 94.

Plant, division of cells, 41 ; absorption of water by, 58.

Planula, nematocysts in, 3; from blastula by unequal growth, 6; from isolated blastomeres, 181; giant, from fused blastulac, 202.

Plate, medullnry, see Medullary; plate, white, in inverted eggs, 85.

Platyhelmia, excretory tubules of, 6; segmentation, 54.

Pluteus, in light of various colours, 96; ciliary movement of, 135; effect of potassium, sodium, lithium, 137; necessity of various elements for, 142 sqq.; partial, 194-196, 199, 200; hybrid, 258 13;

335

262; arms of, dependent on skeleton, 188, 144, 150, 195, 275; growth rate of arms, 70, 71.

Podarke, crossed polar furrows, 46.

Pole cells, see Teloblast.

Polar areas, in Frog's eggs exposed to electric currents, and in other structures. 92, 98; bodies, asters of same size in, 31 ; in Ascaris m’grovenosa, 33; in Callidina, 34; division, violate Hertwig’s rule, 84 ; furrows, see Furrows; lobe, see globe; nuclei, see Nucleus; rings,

51.

Polarity of Echinoid eg, 183; see also Egg-axis.

Polarization, meridional, in F1-og‘s egg, S3; of egg-particles, 281, 286.

Polyaster, 128.

Polyclads, 25.

Polychaeta, influence of gravity on eggs, 78; pressure experiments, 89, 213.

Polyspermy, pathological, 107; due to poisons, 128; irregular distribution of chromosomes in, 253, 264, 265.

Polyzoa, 22.

Position, changes of position in development, 3; Davenport's cata logue of, 4 sqq. ; fate a function of, 188, 282.

Post-generation of missing half-embryo in Frog, 161, 162; denied by Hertwig and Morgan, 170, 171; confirmed by Endres, 171.

Post-trochal region, 224.

Potassium bichromate, 94; bromide, 123, 132; nitrate, 123; sulphate, 123; iodide, 132; chloride, 123, 133; cyanide, prolongs life, 131, 132 ; larvae of Echinoids, 137, 146 ; necessity of, 146.

Potentialities, altered by chemical reagents, 140; limitation of, 175, 176, 180, 181, 191, 194, 201, 204, 242-244, 246, 277, 281, 284, 286; due to lack of material, 182, 194, 201, 225, 242, 281, 291; due to lack of specific material, 180, 201, 217, 225, 242, 243, 281, 291.

Practical concept of freedom, 289.

Predetermination of embryonic axes, see Embryonic axes; physicochemical, 285.

Prediction, the function of science, 299.

Preformation of organ-forming stances, 207, 227, 241, 286.

sub336

Preformation hypothesis, sec Evolution.

Prelocalization, 207, 222, 227, 241.

Pressure, atmospheric, see Atmospheric ; osmotic, see Osmotic ; experiments on eggs of Frog, 84-37, 40-168; on eggs of Echinoderms, 37, 38, 185, 186; on eggs of Nereis, 39, 213; on eggs of Beriie, 39; as a meansof preventing cell-division, 55, 56.

Primary qualities, 300.

Primitive streak absent, 104.

P1-i1;ciple of germinal localization, 1 .

Principle of least surfaces, 41-44; in spiral segmentation, 45-47; disobeyed in radial and bilateral types, 49.

Proctodaeum, 9.

Pronuclei, causes of union of, 130; ggfih male and female, not needed,

Proportionality, 293, 295; of parts in partial larvae, 198-201, 290 ; in one larva from two blastulae, 202.

Prototroch, 218, 224.

Protozoa, alteration of shape during division, 48; senile decay, 65 ; enucleate fragments of, 254; in electric current, 93.

Pseudo-gastrula, 287.

Pseudo-triaster, —tetraster, 108, 129.

Psychoid, 291, 297.

Puberty, increase in growth-rate at, 65 ; increase in variability at, 73 ; increase in value of correlation coefiicient at, 75, 76.

Purposiveness, 286-289, 296, 299.

Purposes, see Purposiveness.

Pyrasoma, 24.

Quadripolar mitosis, 263-265, 267.

Qualities, inheritable, see Inlieritable.

Qugaggties, primary and secondary,

Qualitative division of nucleus, see Nucleus.

Quartettes of xnicromeres in ‘spiral’ eggs, 25, 80, 213; isolated, 215, 221.

Quliéigne, effect on fertilization, 128 Rabbit, decline of growth-rate, postnatal, 62, 65; prenatal, 68.

Radial segmentation, see Segmentation; radial symmetry, sea Symmetry.

Rana esculenta, bilateral segmentation, 26, 28; obliquity of egg-axis,

INDEX OF SUBJECTS

81, 168; cardinal temperature points, 100; eifects of salt, 118; brain and eyes of tadpole remo\ ed, 175; fusca, segmentation, 28, 47, 53; cardinal temperature points, 97; influence of heat and cold, 97-100; effect of salts and other substances, 119—123; artificial parthenogenesis, 124; symmetry of egg, 8], 163, 247, 248; formation of lens, 275; palustris, symmetry of eg, 81, 247; influence of cold, 100; temporaria, symmetry of egg, 81, 163, 247, 248; virescans, influence of cold, 100.

Rate of cell-division, see Cell—division ; of Development, see Development ; of growth, see Growth.

Ratio between nucleus and cytoplasm, 65, 268, 269.

Rearrangement of cells, 11.

Recapitulation theory, 12, 16.

Red light, 94-96.

Redistribution of yolk and protoplasm in inverted eggs, 84; of organ-forming substances, 207, 208, 226, 227.

Reducing agents, 131.

Reflective judgement, 287, 288.

Reflex movements of tadpoles deprived of brains, 176.

Regeneration, 290; a form of development, 1 ; of head of Tubularia, 114, 144 ; and Reserve Idioplasson, 159; of missing half-larva in Ctencphora, 210; in Ascidia, 239; necessity of nucleus for, 254; of lens, 276; nucleus in, 284, 285.

Regulation, 290.

Rsnilla, 55.

Reproduction, sexual.1 ; Aristotelian view of, 13, 294-296.

Reserve-idioplasm, 159, 161, 266.

Resistance to injury, capacity for, alters, 104.

Respiration of Chick, 109, 113; of Frog's egg, 110, 111, 112 ; of Telecstean ova, 111; of Echinoid ova, 112.

Responses to stimuli, 12, 20, 114, 272-277, 288-285.

Restriction, genetic, 246, 277 ; see also Potentialities, limitation of.

Retardation of development, by sound vibrations, 90; by light of certain colours, 94-96; at low temperatures, 97, 99, 100;- without oxygen, 110, 111 ; by desiccation, 115; by increased osmotic pressure, 117; in absence of potassium, 146 ; and INDEX OF SUBJECTS

magnesium, 148; and calcium, 150 ; with decrease of germinal VJI16, 200, 204.

Rhumkorfl coil, 91.

Rhynchelmis, 251.

Rhythm of development, 3.

Rind at surface of blastomeres, 54.

Ringer's solution, 120.

Rotatiomperpetual, of Hen’s eggs, 90 ; of pronuclei in Ascaris nigrovenasa, 34: in Diplogasler, 34; not in Oallidina, 34; of tirst two blastemeres in Oallidina, 34; of micromeres on macromeres, 47.

Rotation structure, ‘of ova, 79.

Rotifera, 26.

Rubidium, 146.

Rule, of Balfour, 29, 88; exceptions to, 80; of Hertwig, 31, 32, 85; confirmed in Ascaris nigrovenosa, 34; and in Diplogaster, 34; by pressure experiments, 34 sqq. ; violated, by polar divisions, &c., 34 ; of Pfliiger, 82, 85.

Sagittal plane and first furrow in Frog, 17, 159, 165-168; in Cteno— phora, 209; in Newt, 175; in Ascidia, 229, 235; and plane of symmetry, 80, 165, 229, 235; determined by gravity, 82, 84; and streaming meridian, 84.

Salmo lens, 276; see also Trout.

Salps, blastomeres of, 5, 28, 54; rearrangement of cells, 11.

Salt-solution as a medium, 45, 53; see also Sodium chloride.

Salts of various kinds, malformations in, 119 sqq., 182, 276; artificial parthenogenesis, 123, 124.

Salvelin-Is, 178.

Sauropsida, blastoderm of, 6.

Science, the scope and functions of, 297 sqq.

Sciences, relation of, to one another, 299, 300.

Scleroblasts of Sponges, 3.

Sclerotome, 11.

Sea-urchin, sec Eohinoids, Pluteus, Echinus, Sphaerechinus, Strongmacentrotus, Arbacia.

Sea-water, calcium-free, used to separate blastomeres, 45, 190.

Sea-water, composition of, 141; artificial, 142.

Secondary qualities, 800.

Secretion of substances in growth, 258.

Segmental duct, splitting of, 6.

JIIKIIIOH

growth of, 5 ;

N

337

Segmentation of the ovum, a factor in development, 2, 279; the beginning of development, 22; and differentiation, see Cell-division, Differentiation; a mosaic, 17, 19, 158, 213, 236, 245, 246; types of, 22

sqq. ; radial, 22, 49, 53; spiral, 25,‘

30, 45-47, 52, 204; bilateral, 26, 49, 52, 229, 285 ; isobilateral, 26, 208; irregular, 28, 54, 55; periods of spiral, radial, bilateral, 26; types pass into one another, 28; meroblastic, in Vertebrata, 24; in Arthropods, 24; in Cephalopods, 27; in centrifugalized Frog's egg, 29, 88; as a result of heat, 97; in salts, solutions of, 119; causes of pattern of, 29 sqq., 197, 246, 266; and egg—axis, 81; in compressed eggs, 34-40; influence of gravity on, 78 sqq. ; effect of electricity on, 92; of heat, 97, 105; of cold, 100 ; of altered osmotic pressure. 117, 118 ; of chemical poisons, 119, 121, 128-130; of lack of oxygen, 111, 112; without sulphate, 143; without chlorine, 145; without sodium, 145; without potassium, 145; without magnesium, 145; in neutral media, 151 ; without calcium, 150 ; irregularities of, produced by heat, 105, 187; by shaking, 188; altered osmotic pressure, 117, 118; by dilution of sea-water, 187 ; alkaloids, 128-130; by calciumfree sea-water, 45, 188, 190; by double fertilization, 264, 265; of isolated blastomeres, total. 173, 178, 180, 181,230; partial, 190, 204, 205, 210, 211, 215 sqq., 229, 237 ; of eggfragments, I95-197, 207, 212,226,227.

Segmentation cavity, 11; absent in Stereoblastulae, 128; reduced without potassium, 146; in Hemiblastula, 159.

Segmentation of mesoderm, 11; of neural crest, 11.

Selective death—rate, 74.

Selenium, 144.

Self-differentiation, sec Differentiation.

Senescence, 65.

Senile decay, 65.

Sense-organ of Ctenophora, 211 ; see also Apical organ.

Separation of blastomeres, see Blastemeres.

Septa, of corpus luteum, 5.

Serosa, of Sipzmculus, 9.

Serpula, 272. 338 INDEX OF

Serranus, 178.

Sertulareln, 272.

Sertula-ria, 272.

Sexual reproduction, 1 ; Aristotelian view of, 13, 294-296.

Shaking eggs, a means of disarranging blastomeres, 188 ; or separating them, 190; prevents division of centmsome, 265, 267.

Shape of cells, 29; altered by spindle, 48.

Shocks given to eggs, 89.

Silicon, 141.

Silk-worms, exposed to influence of magnetism, 91.

Sipunculoids, 22.

Sipunculus, 9.

Siphonophora, 181.

Size, increase of, see Growth; of organisms, 65; of cells, determined by yolk, 29, 48; in partial larvae, 199; of bubbles, 43, 46; of nucleus, sea Nucleus; of partial larvae and their organs: in the Newt, 173; in Fishes, 178; in Amphioxus, 181; in Echinoids, 198, 199; in Nemertines, 206.

Skeletal cells, and notochord, 5.

Skeleton, of Chick, malformations of, 90; of Pluteus, in potassium, 137; and lithium salts, 138; Without sulphate, 144; without potassium, 146; without magnesium, 147 ; without calcium, 149; without carbonate, 150; in bromides, 145; in neutral media, 151; number of arms depends on number of spicules, 138, 144, 150, 195, 275; dependent of nucleus, 261; of hybrids, 259-262.

Soap films, 41, 42; bubbles, 43-47.

Sodium, chloride, used to suppress cell-division, 56, 117; to produce abnormalities, 119, 120, 133-135; larvae of Echinoids, 137; bromide, 120, 134; sulphate, 135; nitrate, 135; butyrate, 140 ; formate, 145; hydrate, 151, 262; acclimatization to, 136; effect on ciliary and muscular movement, 185; necessity of, 145.

Solenoid, Tesla's, 91.

Solutions, chemically equivalent, 140; equimolecular, 140; hypertonic, 116, 117, 120-122, 128, 124; hypotonic, 118; isotonic, 120, 123, 124, 140, 142.

Somatic cells of Aacaris, 252, 258.

Somatopleure, fused with allantois, and trophoblast, 9.

SUBJECTS

Somites, fusion of, 11.

Soul, Aristotelian doctrine of, 292297; nutritive, 18, 293; perceptive, 13, 293; reasoning, 294 ; and body, 292.

Sound-vibrations, effect of, 90.

Specific gravity of yolk, 78, 79.

Spermatozoon, entrance of, and direction of first furrow, 40, 185, 247, 248; entrance of, and gray crescent, 80, 165, 247, 248; entrance of, and alteration of eggstructure, 80, 165, 222, 232, 247251 ; sperm-sphere and aster, 123; nature of stimulus imparted by, 124; effect of alkaloids on, 129; without potassium, 146; without magnesium, 147.

Sphaerechinus, effect of heat on, 105, 106, 187; potassium and lithium larvae, 137-140; necessity of cortain elements for, 142 sqq.; ‘pressure experiments, 186; isolated blastomeres, 191 ; blastomeres disarranged, 187; pieces of blastulac and gastrulae, 194, 195; size of partial larvae and their organs, 198, 200; one embryo from two blastulae, 201, 202; hybridization experiments, 258-262.

Spina bifida, in centrifugalized eggs, 88; as a result of heat, 99; ofocold, 100; of lack of oxygen, 11 .

Spindle, nuclear, direction of elongation of, 31, 32, 34, 39, 48, 248; oblique in ‘spiral' eggs, 32; rigidity of, 48; in artificial parthenogenesis, 124, 195; in karyokinetic plane, 185.

Spiral segmentation, see Segmentation ; asters, see Asters.

Spirogyra, 269.

Spleen of Vertebrates, 5.

Splitting of cell-aggregates, 6, 9, 11.

Sponges, larval skeleton, 2, 3; gemmule of, 5, 11 ; segmentation of, 22, 47; larva cf, 6; unipolar immigration in, 11.

Spongilla, 47.

Sports, 141.

Stages, series of, in development, sec Rhythm.

Standard deviation, 71.

Static teleology, 291, 292.

Stature, human, change in rate of increase, 68-70; variability of, 74 ; correlations with other magnitudes, 75.

Stereoblastulae, 128. INDEX OF

sternum, girth round, rate of growth, 70.

Stisiuli, 12, 20, 272-277, 288-285; of spermatozoon in fertilization, 128, 252; exerted by spicules of Pluteus, 137. 275; directive, in post-generation, 162.

Stolen, see Hydroids.

Stomodaeum, 9; formed in Aneuteria, 106; in Exogastrulae, 137; absent without potassium, 146; formed from isolated ectoderm, ‘-95; of Ctenophora, 210, 211.

Stratification of organ-forming substances, 242, 280.

Strongylocentrotus lividus, segmentation of, 23 ; egg stretched, 39; decline of growth-rate, 67; growth-rate of arms of Pluteus, 70; decline of variability in, 71 ; eggs exposed to heat, 107; to action of alkaloids, 126 sqq. ; normal development, 183-185; mieromeres suppressed, 186; hybridization experiments, 261, 262; purpuratus, heterogeneous cross-fertilization, 262.

Strontium, 156; bromide, 182, 133.

Structure, increase of, 2, 279 ; of egg, see Egg-axis, Symmetry of egg.

Strychnine, eggs of Bufo, 120; effect on fertilization, 128-130; on Chick, 132.

Substances, organ-forming in cytoplasm, I9, 207, 208, 217, 224, 225, 228, 233, 236, 240, 241, 246, 280, 286; specific action of substances present in sea-water, 152.

Succession, in the formation of parts, 13.

Suckers, 239.

Sulphates, 123; of quinine, 128-130 ; of magnesium, 135; of sodium, 135; necessity of, 143, 144.

Sulph-ion, see Sulphate.

Sulphuric acid, 145.

Superficial cell-aggregates, see Cell.

Surface, area of, in partial larvae, 198, 269; area of nuclei and number of chromosomes, 268.

Surface-tension, 41 sqq., 55, 56.

Surfaces of contact between blastemeres, in radial segmentation, 22; in spiral segmentation, 45-47; between isolated cells, 54; between soap-bubbles, 43; between oildrops, 49 sqq.

Suspension of development, at low temperatures, 97, 99, 102, 104.

Swelling after shrinkage in hypertonic solutions, 124.

SUBJECTS 339

Sycandra, 22.

Symmetry, bilateral, of egg cytoplasm, 33, 80, 163, 232, 247, 280, 281; radial, of egg, 79, 163, 204, 222, 232, 280; bilateral, and sagittal plane, 80, 229, 235, 244 ; produced by gravity, 82, 84, 87; radial, of Plutei without sulphate, 144; hilateral and first furrow, 167, 229, 235.

System, equipotential, 176, 277 ; inequipotential, 176, 277.

Systems of lamellae, see Lamellae; of drops, see Drops.

Tadpole, tail of, phagocytosis in, 5; absorption of water, 58. 59; rate of growth in, 67; influence of light on, 94; effect of pure oxygen, 113, 114; effect of increased atmospheric pressure on, 114; brain and eyes removed, 175, 275 ; formation of lens and cornea, 275-277.

Tail of Tadpole, phagocytosis in, 5; doubled at high temperatures, 99.

Taxis, Tactic, see Stimuli and Responscs.

Teleology, of Kant, 286-289 ; dynamic, 291, 296; of Aristotle, 297.

Teleostei, nervous system of, 6, 138; segmentation, 26, 35; injuries to germ-ring, 178; effect of fertilization, 251.

Tellurium, 144.

Teloblast, continued division in same direction, 29; continued unequal division, 30 ; unequal asters in, 31.

Telolecithal eggs, 24, 30.

Temperature, as affecting growth, 2, 59; cardinal points, for Frog’s egg_ 97; for Hen’s egg, 102; for Plutei, 107 ; alteration of variability with, 107; high, see Heat; low, see Cold.

Tendon, 5.

Tension, see Surface-tension, Decomposition-tension.

Tentacles, branching of, 6.

Teratology, 119, 155, 156.

Teredo, 26.

Tetrahedral arrangement of cells, 24, 25, 26, 28, 29, 47; of soapbubbles, 43.

Tetrasters, 107; produced by alkaloids, 128.

Thalamencephalon, roof of, 7.

Thelykaryotic, 267..

Theory, ‘Mosaic’, or self-differentian tion, 17, 19, 158 ; analytical, of Driescli, - 280-286. 340

Thickenings of cell-aggregates, see Cells, movements of.

Thigh, rate of growth, 70.

Thigmotropism, 272, 275-277.

Thinnings of cell—aggregates, see Cells, movements of.

Thio-sulphate, 144.

Tlfimus, concentric corpuscles of,

Toad, 82, 102.

Totipotent, parts, 76; see also Whole nuclei, 266, 283, 284, 285.

Toxicity, 122, 135, 136.

Toxines, bacterial. 132.

Totcopneusfes, 185, 250.

Transportation, by cells, see Cells, movements of.

Trematoda, segmentation, 28.

Triasters, 107 ; produced by alkaloids, 128.

Triclads, blastomeres of, 5, 54, 273; segmentation, 28, 55.

Tripolar mitosis, 265.

Trochoblasts, 213, 220.

Trochophore, 224, 225.

Trochus, 26, 30, 45-47.

Trophoblast of Mammalia, 7; fusion of, with embryonic plate, 9; {used with somatopleure, 9; coenocytic and syncytial, 55.

Trophochromatin, 258.

Tropism, Tropic, see Stimuli Responses.

Trout eggs placed between poles of a magnet, 91 ; between electrodes, 91 ; in light of various colours, 95.

Truncus arteriosus of Mammals, splitting of, 6.

Tubercle toxine, 132.

Tubularia, 114, 144.

Tunicata, follicle cells of, 5.

Turbellaria, yolk-glands, 5.

'1‘urgor_of plant-cells, 246.

and

Umbrella, segmentation, 26, 30; flattening of blastomeres, 45 ; parallel polar furrows, 46. ,

Understanding, 301.

Unequal division, see Cell-division ; of oil-drops, 62; numbers of chromosomes, see Chromosomes.

Unio, segmentation, 25, 80, 47; unequal asters, 30 ; flattening of blastomeres, 45; crossed polar furrows, 46.

Unipolar, sec Immigration.

Units, representative of inheritable qualities, 19, 159, 246, 246, 279, 280.

INDEX OF SUBJECTS

Urea, Frog's eg, 121; notochordal tissue, 184; nuclei, 135. Urodela, notochord in, 8, 183.

Vacuolation of cells of spaerechinue, 146, 261.

Valency, 136.

Variability, decline of, during growth, 71-74 ; increased at time of puberty, 78; causes of decline, 74 ; increased by an adverse change of conditions, 74, 141, 156; in period, 74.

Variation, see Variability.

Vasa eiferentia, union of, with mesonephric tubules, 6.

Vegetative cells, see Cells.

Vegetative pole, blastopore at, 244.

Veliger, 217.

Ventricosity, of shell of Littorina, 71.

Vertebral column, rate of growth, 70.

Vertebrates, spleen of, 5; bone and tendon, 5; vitreous body, 5; vasa etferentia, 6; nerve-crest, 11; segmental duct, 5; lens, 7; auditory vesicle, 6; limb-buds, 11 ; medulla, 7 ; artificial parthenogenesis, 124; thalamencephalon, 7; segmentation, 22, 24, 47.

Viole de Parme, 94. Violet light, 94-96. Vital constant, 291. Vitalism, 291 sqq.

Vitellophags, 4, 273 ; vitelline membrane, see Membrane.

Vitreous body of Vertebrate eye, 6.

Volume of partial larvae, 199 ; of cells, and number of chromosomes, 26:; of nucleus, and cell-surface, 26 .

Waist, rate of growth, 70.

Water, absorption of, in growth, 2, 58, 59, 115, 116; in liypotonic solutions, 118; decrease of, in later stages, 58 ; evaporation of, from albumen, 115; not absorbed by egg of Frog, 123.

- withdrawal of, 119; in fertilization, 128 ; and artificial parthenogenesis, 128, 124; aggregated about apical body and middle-piece of spermatozoon, 123.

-— fresh, 117, 136; distilled, 136.

Weight, increase of, as a measure of growth, 58 sqq.; correlations with other magnitudes, 75; loss of, in Hen's egg, 115.

plate, in inverted Frog's eggs, INDEX OF SUBJECTS 341

Whole larvae from blastomeres or 29, 48; specific gravity of, 78; egg-fragments, in the Newt, 178; descent of, in inverted eggs, 84; 1.1 Teleostei, 178; in Amphioxus, in centrifugalized eggs, 88; in ISO: in Coelenterates, 181 ; in jured by heat, 97; by cold, 98; by Echinoderms, 198, 197 ; in Nemer- salts, 119, 185; elfect of removal

tines, 204, 207. in Teleostei, 178; of Cynthia, 280 ; Withdrawal of water, see Water. . -cells of Triclads ‘and Salps, 6 ; Woman, see Human being. -gland of Turbellaria, 5 ; -1ol_>e, see Worcester, Mass, school-children, Lobe, polar; -nuclei in centrifugagrowth of, 63. lized Fi-og’s egg, 30, 88; in eggs grown in salt, 119; -plug persistent

xxlol’ 54' 313 8 result ofheat, ; Of cold, ;

ln.B0l11tl0nS of salts, &c., 119 sqq. ;

-sac ruptured in eggs that are not Yellow light, 94-96. turned, 89; of Fundulus, pigment Yolk, 2; influence of, in cleavage, 24, of, 94, 111, 114, 274.