624 



PATTERNS AND PROBLEMS OF DEVELOPMENT 



lated in the testis to a blastophore or cytophore or a particular kind of 

 accessory cell. The cytophore, characteristic of many invertebrates, has 

 somewhat different origin in different species. Successive divisions of 



Fig. 200, /I -C— Fish and amphibian spermatozoa. .4, Raja; B, Triton {A and B from 

 Ballowitz, iSgoc); C, Bombinator (from Broman, 1900). 



spermatogonia and spermatocytes are cytoplasmically incomplete in some 

 forms; and more or less spherical groups of cells, separate peripherally, 

 continuous centrally, result, the central cytoplasm becoming the cyto- 

 phore (Fig. 201, ^). In other species the cytophore develops from degen- 

 erated cells in the center of a mass (Fig. 201, B). The spermatozoa de- 



