Fig. 9. Section through a germinal disc in which the segmentation is completed. It shews the larger collection of cells at the embryonic end of the germinal disc than at the non-embryonic. ep. epiblast.
[79] Rochen und Haie.
[80] The germinal disc figured was from the egg of a Scyllium stellare and not Pristiurus, but I have also sections of a Pristiurus egg of the same age, which do not differ materially from the Scyllium sections.
[81] In the figure of this stage, I have inserted nuclei in all the segments. In the section from which the figure was taken, nuclei were not to be seen in many of the segments, but I have not a question that they were present in all of them. The difficulty of seeing them is, in part, due to the yolk-spherules and in part to the thinness of the section as compared with the diameter of a segmentation sphere.
[82] Loc. cit.
[83] Archiv f. Micr. Anat. XI. p. 592.
[84] “Entwicklungsgeschicte der Najaden,” LXXI. Bd. der Sitz. der k. Acad. Wien, 1875.
[85] Text-Book of Botany, English trans. p. 19.
[86] “Entw. d. Geryonideneies.” Jenaische Zeitschrift, Bd. VII.
[87] Loc. cit.