File:Conklin 1905 fig27-33.jpg

Figs. XXVII XXXVIII. Gastrulation of an ascidian, of Amphioxus and of an Amphibian

Schematic representations of three stages in the gastrulation of an ascidian, of Amphioxus and of an amphibian to show their supposed resemblances in (1) Axial Relations, (2) Closure of Blastopore, (3l Origin of Neural Plate, (4) of Chorda and (5) of Mesoderm. The position assigned to the polar bodies in Amphioxus and the amphibian is to a certain extent hypothetical. The head of the arrow marks approximately the anterior limit of the neural plate; the tail of the arrow, the median mesenchyme cells in the posterior (ventral) lip of the blastopore. The mesodermal cells or areas are shaded by entire or broken lines.

Figs. XXVII XXIX. Right halves of bisected gastrulae of Cynthia ; the chorda cells are shaded by coarse stipples, the neural plate cells in. p.) by line stipples. The muscle cells (m.s.) lie lateral to the mesenchyme cells (m'cfa l and by the overgrowth of the anterior (dorsal) lip of the blastopore are separated from the mesenchyme cells anteriorly (XXIX),

Figs. XXX XXXII, Right halves of bisected gastrula- of Amphioxus (mainly after Hatschek I. In the two earlier stages the existence and position of the mesoderm is hypothetical, being based upon the conditions found in ascidians.

Figs. XXX I II -XXX V. Right halves of bisected gastrula of the frog (mainly after Kopsch I. The areas shaded by stippled lines represent the supposed position of the mesoderm, here covered in endoderm and yolk.

Figs. XXXVI XXXVIII. Dorsal views of late gastrnte of ascidian (XXXVI), Amphioxus (XXXVII), and frog (XXXVIII), The circles marked 1, 2, 3. 4 indicate successive stages in the closure of the blastopore. The actual position of the mesoderm in the ascidian and its supposed position in Amphioxus and the frog is shown by the radiating lines around the blastopore. The unshaded area (Ch.) anterior to the blastopore and between the halves of the mesoderm represents the plate of chorda cells.

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Conklin Figures: Fig 1-2 | Fig 3-6 | Fig 7-8 | Fig 9-12 | Fig 13-16 | Fig 17-20 | Fig 21-24 | Fig 25-26 | Fig 27-33 | Fig 34-35 | Plate I | Plate II | Plate III | Plate IV | Plate V | Plate VI | Plate VII | Plate VIII | Plate IX | Plate X | Plate XI | Plate XII

Reference

Conklin EG. The Organization and Cell-Lineage of the Ascidian Egg (1905) J. Acad., Nat. Sci. Phila. 13, 1.

Conklin 1905 TOC: I. The Ovarian Egg | II. Maturation and Fertilization | III. Orientation of Egg and Embryo | IV. Cell-Lineage | V. Later Development | VI. Comparisons with A.mphioxus and Amphibia | VII. The Organization of the Egg | Summary | Literature Cited | Explanation of Figures

Cite this page: Hill, M.A. (2024, April 19) Embryology Conklin 1905 fig27-33.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Conklin_1905_fig27-33.jpg

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