FATE OF BLASTOPORE, ETC., IX CHELOXIA. JQJ 



Hertwig says in regard to the simple growing edge (Umvvachsungs- 

 rand) applies to it. Unfortunately I have no observation of ni}^ own, 

 l)ut the work of H. A'ikchow ( 92) proves this abundantly. 



This goes to prove that the edge of the blastoderm in Elasmo- 

 branchii is the blastopore edge and not the growing edge, while the edge 

 of the blastoderm in Sauropsida, is the (jrowing edge and not the blasto- 

 pore edge, which is fcnind in their eggs in that part surrounding a 

 small remnant of the primary yolk-mass situated near the embryo. 



The objection which Hektwig raises against the idea of a yolk- 

 blastopore is thus not insurmountable. 



