626 



PATTERNS AND PROBLEMS OF DEVELOPMENT 



termination of axiate pattern by the relation to the cytophore or acces- 

 sory cell (see Broman, 1902). It seems probable that in at least some forms 

 with cytophore the axiate pattern of the spermatozoon is determined by 

 the difference in conditions between the pole toward the cytophore and 



Fig. 202, A, B. — Relation of mammalian spermatids to Sertoli cells. A, rat (after von 

 Lenhossek, 1898); B, man (after Broman, 1902). 



the peripheral pole. In many cases there is cytoplasmic continuity with 

 the cytophore until development of pattern is far advanced. A tropistic 

 reaction is, of course, possible in the cases of secondary association with 

 an accessory cell, as in Figure 202, A and B, but does not appear very 

 probable. The polar position of the nuclei suggests a reaction to a factor 



