SPERM ATOGENESIS OF THE EARTHWORM 157 



The nuclei increase by division and take a position at the periphery of the 

 protoplasmic mass, where further multiplication follows until there are 

 from 32 to 64 nuclei. Protoplasmic furrows then cut in around each of 



:. : - * : .. 

 ;;":. ' .' ' ' 



'. '.'./. ; '.' ' 

 * ' f ' ':'.' ". ".'* 



FIG. 64. Stages in the development of spermatozoa of the earthworm. 



(From Calkins.) 



the peripheral nuclei. Each of these nuclei then begins to elongate, and 

 to transform into a spermatozoon. The nucleus forms the head of the 



