Archive image from page 91 of The development of the frog's. The development of the frog's egg; an introduction to experimental embryology . developmentoffro00morg Year: 1897 Fig. 2S. —Two '• spiua-bilida' embryos. (After Hertwig.) A. Earlier, B. older stage (different embryos). is surrounded by a groove, and outside of the groove there is a bounding darker ridge. In the anterior portion of the white is seen a crescent-shaped depression. A cross-section through the middle of the body of an embryo similar to the last is shown in Fig. 29, A. The exposed yolk is seen at Y. On each side of this t

---

Archive image from page 91 of The development of the frog's. The development of the frog's egg; an introduction to experimental embryology . developmentoffro00morg Year: 1897 Fig. 2S. —Two '• spiua-bilida' embryos. (After Hertwig.) A. Earlier, B. older stage (different embryos). is surrounded by a groove, and outside of the groove there is a bounding darker ridge. In the anterior portion of the white is seen a crescent-shaped depression. A cross-section through the middle of the body of an embryo similar to the last is shown in Fig. 29, A. The exposed yolk is seen at Y. On each side of this there is a depression, and beyond the depres- sion a thickened ridge composed of ectoderm cells. Each ridge passes over on its outer side into the ectoderm that covers all the lower part of the embryo. Even in their present stage

---

Size: 1195px × 1674px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: 1890, 1897, archive, book, bookauthor, bookdecade, bookpublisher, booksubject, bookyear, drawing, embryology, historical, history, illustration, image, morgan_thomas_hunt_1866_1945, new_york_the_macmillan_company_etc_etc_, page, picture, print, reference, vintage