21 DAVS 

 CiuDiLVElN 



Fig. 337. Ventral views of developing allantoic, hepatic portal, and inferior caval veins 

 in chick. (Diagrams C and D are adapted from figures in Lillie, 1930, The Development 

 of the Chick, Henry Holt, N. Y., after Hochstetter; diagrams F-H are adapted, consider- 

 ably modified, from Miller, 1903, Am. J. Anat. 2.) (A) Diagram of converging veins 

 of heart during early third day of incubation. (B) Same at end of third and early 

 fourth days. (C) Middle fourth day. (D) End of fourth and early fifth days. (E) 

 Seventh to eighth days. (F) Development of inferior vena cava at end of fourth and 

 beginning of fifth day of incubation. (G) Same, 6 7 days. (H) Same, fourteenth day. 

 (I) Same at about hatching time, 20-21 days. 



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