70 



CYTOLOGY 



CHAP. 



this body is separated from the 

 centrosomes, and comparatively 

 large. 



The changes undergone by the 

 nucleus during the development of 

 the spermatozoon are, so far as can 

 be seen, little more than a progress- 

 ive concentration. 



The idiosome applies itself to the 

 end of the nucleus farthest from 

 the centrosomes, and there becomes 



|] 



-Fig. 30. 



Metamorphosis of the spermatid into the sperma- 

 tozoon. Diagrammatized and simplified trom the 

 accounts of the process in the guinea-pig by Meves 

 {A.m.A., 1899), and Duesberg {A.Z., 191 1). a, acro- 

 some ; a.f, axial filament of tail ; c, centrosome ; ch, 

 chondriosomes ; h, head (nucleus) of spermatozoon ; i, 

 idiosome ; m, middle piece of spermatozoon with two 

 centrosomes and spiral chondriosome band; n, nucleus; 

 r, cytoplasm of spermatid which is thrown off ; t, tail 

 of spermatozoon. 



D 



A B 



Fig. 31. 



Various spermatozoa. (After Retzius, 1909.) A, 

 Notodromas ; B, Lociista ; C, Turdus ; D, Homo ; 

 E, Galathea. 



