SPERMATOGENESIS 



2 7 



consists of a head, which is essentially the nucleus, a middle piece containing 

 the centrosome, and a tail; but the form of the head is very different from 



FIG. 21. SPERMATOGENESIS IN Dissosteira Carolina. Xi4So. (Davis.) 



A-F, successive stages in the division of a secondary spermatocyte into spermatids. G-J, successive stages 

 in the transformation of spermatids into spermatozoa. 



that in the grasshopper. It will be described in a later chapter 



Although the spermatozoa of the grasshopper appear alike, it has been 

 shown that one-half of them contain eleven chromosomes, and one-half 



