10 



COMPARATIVE ANATOMY 



A1.-..I- 



FIG. 8, A, B, AND C. DIAGRAMS ILLUSTRATING THE FORMATION OF THE AMNION, 

 ALLANTOIS, AND YOLK-SAC. A AND B, IN LONGITUDINAL SECTION ; C, IN 

 TRANSVERSE SECTION. 



JK, embryo ; Dh, alimentary cavity ; Do, yolk-sac ; t, vitello-intestinal duct ; PP, 

 ccelorne ; Ah, amniotic cavity ; AF, amniotic fold ; A, amnion ; At, allantois ; 

 n, somatopleure ; b, splanchnopleure ; M, medullary cord ; C, notochord. 



