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 



mes 



Fig. 17. Rabbit embryonal areas. 



D is a transverse section through A, 1 72 hours ; E through B, 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 ; 

 mes mesoderm ; ps primitive streak ; prg primitive groove. 



