CXORSAL AORT 



DUCT OF C 



OMPHALOMESENTERIC 



IVITELLINEl 



ARTERY 



Fig. 336. Early development of the circulatory system in the chick. (A) Primitive 

 vitelline (omphalomesenteric) veins, heart, ventral aorta, and the first or mandibular 

 pair of aortal arches. About stage 10 of Hamburger and Hamilton, 1951, J. Morph. 88. 

 Approximately 33-38 hrs. of incubation. (A') Lateral view of same. (B) Lateral 

 view of chick circulatory system of about 45-50 hrs. of incubation. (About Hamburger 

 and Hamilton stage 13.) (B') Same, showing common cardinal vein (duct of Cuvier). 

 (C) Circulatory system of chick during early part of third day of incubation. (About 

 Hamburger and Hamilton stage 15.) (D) Circulatory system of chick embryo about 

 72 hrs. incubation. 



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