CLEAVAGE 



255 



TABLE OF THE CELL LINEAGE OF ASCARIS 



Modified from Zur Strassen 

 (Letters in parenthesis are the notation of Zur Strassen, Boveri and others) 



* Primordial germ cell. 



The study of cleavage from this point of view discloses the 

 fact, of the utmost importance in development, that blasto- 

 meres may be individually and specifically recognizable as 

 morphological and morphogenetic units. They bear much the 

 same relation to the whole cell group that the organs and tissues 



