372 



THE MALE REPRODUCTIVE ORGANS 



the spiral cytoplasmic fin of the flattened spermatozoa of amphib- 

 ians, whose border contains a second filament, the marginal fibre ; 

 (2) the faintly chromatic ring or spiral which sometimes occurs 

 near the posterior end of the middle piece 

 or entwined about its axial filament. These 

 structures have not, however, been demon- 

 strated in the spermatosomes of man. 



The spermatozoa may be regarded as 

 metamorphosed germ cells which arise by 

 the direct transformation of the spermatids 

 in the seminiferous tubules of the testicle. 

 As a result of this transformation, so far as 

 has been satisfactorily demonstrated, the nu- 

 cleus of the spermatid becomes the chromatic 

 body or nucleus of the spermatozoon : the 

 centrosome of the spermatid, usually double, 

 enters the middle piece, the inner centrosome 

 forming the end knob of the axial filament, 

 the outer centrosome either forming the ring 

 body of the middle piece or, like the inner, 

 entering into the formation of the end knob 

 and axial filament ; the arcoplasm (attraction 

 sphere, idiosome of Meves) leaves the centro- 

 somes of the spermatid and in part at least 

 wanders around the nucleus to the opposite 

 pole where it forms the acrosome, the re- 

 mainder of the arcoplasm probably entering 

 into the formation of the cytoplasmic por- 

 tion of the middle piece : the axial filament 

 arises under the influence of the centrosomes 

 (Meves*) or possibly by the direct trans- 

 formation of the outer of these bodies (Korff,f 

 Suzuki I) : and finally, the envelope of the 

 tail piece, and probably also that of the middle piece, arises by 

 the direct transformation of a part of the cytoplasm of the sperma- 

 tid; the remaining portion of the cytoplasm of the spermatid 

 does not enter into the structure of the spermatozoon but is sepa- 

 rately cast off and degenerates. 



FIG. 302. SPERMATOZOA 

 OF VARIOUS ANIMALS. 



A, from the badger; 

 5, from the bat. Eedrawh 

 after Ballowitz. x 1200. 

 (7, from the rat. Hema- 

 tein andeosin. 'x 1200. 



Arch. f. inik. Anat., 1897. f Ibid., 1899. 



\ Anat. Anz., 1898. 



