From Embryology

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Fig. 47. Transverse sections of blastoderm of chick (21 hours' incubation).


a, Section through primitive groove, posterior to Hensen's node.

b, Section through Hensen's node.

"A transverse section through the primitive pit shows essentially the same structural arrangement as in the streak farther caudally (Fig. 47, B). In some birds the pit opens into the archenteron, but not in the chick. The region of the primitive knot also shows the same arrangement, the knot itself being an elevation just in front of the pit. Caudally the primitive groove becomes more shallow and finally disappears, the caudal end of the streak broadening out as the primitive plate."

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Bailey FR. and Miller AM. Text-Book of Embryology (1921) New York: William Wood and Co.

Cite this page: Hill, M.A. (2024, June 24) Embryology Bailey047.jpg. Retrieved from

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