. The development of the frog's egg; an introduction to experimental embryology. Embryology. Fig. 19. — A. Diagram to illustrate overgrowth of dorsal lip of blastopore. I-IV rep- resent different stages. B. Diagram of cross-section through Z-Y of A, to show lateral lips of blastopore, and mesoderm (M), and (IW) inner wall of archeuteric pit. OW. Outer wall. in Fig. 18, F, the egg is represented as having rotated as a whole to bring the embryonic portion above. The changes that take place during the closure of the blasto- pore are perhaps more clearly shown by the following experi- ment. By mea
. The development of the frog's egg; an introduction to experimental embryology. Embryology. Fig. 19. — A. Diagram to illustrate overgrowth of dorsal lip of blastopore. I-IV rep- resent different stages. B. Diagram of cross-section through Z-Y of A, to show lateral lips of blastopore, and mesoderm (M), and (IW) inner wall of archeuteric pit. OW. Outer wall. in Fig. 18, F, the egg is represented as having rotated as a whole to bring the embryonic portion above. The changes that take place during the closure of the blasto- pore are perhaps more clearly shown by the following experi- ment. By means of a fine pointed needle it is easy to puncture the egg slightly at any given point. When the outer surface of the egg is pierced, there follows a protrusion of material as soon as the needle is withdrawn. At other times when the surface is only itidented (7iot pierced) by the needle, there follows a blunt protrusion of material and the surface remains unbroken. In the latter case the marks do not always last as. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Morgan, Thomas Hunt, 1866-1945. New York, The Macmillan company; [etc. , etc. ]
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectembryology, bookyear1
