Development of Rabbit 



33 



drawn out,, but the anterior half of the deuterogenetic area is 

 drawn out to a still greater extent,, the latter appearing as a conical 





HKCS^^^S^uaE/ 

 en 



^"^J^^^kB^ 



t ''~** v 3$'i$f 



&.---&^y^^&5zz^^ 



Fig. 17. Rabbit embryonal areas. 



D is a transverse section through A, 1 72 hours ; # through 5, 180 hours ; F through 

 C, 192 hours; in A the primitive streak is elongated and slightly grooved; 

 in B the primitive streak is at the maximum length and the groove at maxi- 

 mum depth ; in C the groove has disappeared, en endoderm ; ec ectoderm ; 

 mesmesoderm; ps primitive streak; prg primitive groove. 



A. V. E. 



