NATHAN FASTEN. 



EXPLANATION OF PLATE III. 



FIGS. 39 TO 43. Stages in transformation of the spermatid that contains a 

 chromatoid body. In Fig. 43 the chromatoid body is expelled. 



FIGS. 44 TO 47. Stages in the transformation of the spermatid that does not 

 possess a chromatoid body. 



FIGS. 48 TO 64. Later stages in transformation of both types of spermatids. 



FIGS. 65 TO 68. The four types of spermatozoa produced. 



