246 



THE DEVELOPMENT OF THE CHICK 



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Nem. 

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 Jfyp. 



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Fig. 148. — Median sagittal section of an embryo of eight days. 



a. A., Aortic arch. All., Allantois. An., Anus. A. o. m.. Om- 

 phalomesenteric artery. B. F., Bursa Fabricii. b. P., Basilar plate. 

 C. A., Anterior commissure, c. C, Central canal. Ch. op.. Optic 

 chiasma. C. p., posterior Commissure. CI., Cloaca. Cr., Crop, 

 d. Ao., Dorsal aorta. D. Hyp., Duct of the hypophysis. Ep., Epi- 

 physis. Fis. Eus., Fissura Eustachii. Hem., Surface of hemisphere 

 barely touched by section. Hyp., Hypophysis. L. t., Lamina ter- 

 minalis. n. A. 8, neural arch of the eighth vertebra. Nas., Nasal 



