818 



THE REPRODUCTIVE ORGANS 



[CH. LVIII. 



projecting processes of the nurse cells, are large spermatocysts of the 

 first order, derived from the spermatogonia by karyokinesis and 

 growth. Still nearer the lumen of the tube lie the spermatocysts 



FIG. 607. Diagram of a portion of a seminal tubule showing development of spermatozoa. 1, Primi- 

 tive germ cell ; 2, spermatogonia ; 3, spermatocysts of the first order ; 4, spermatocysts of the second 

 order ; 5, spermatids, some with commencement of axial filament ; 6, a nurse cell with spermatida 

 and spermatozoa in various stages of development ; 7, free spermatozoa in lumen of tube ; 8, por- 

 tions of nurse cells. (After Waldeyer.) 



of the second order, which are the daughter-cells of the spermato- 

 cysts of the first order, and the spermatocysts of the second order 

 give rise by divisions to the spermatids which lie next the lumen. 

 The spermatids become embedded in the inner ends of the nurse 

 cells, where they lose their distinct cellular characters and become 



FIG. 608. A spermatid largely 

 magnified. 1, nucleus; 2, 

 nucleolus ; 3, chromatoid 

 body ; 4, idiosome ; 5, centro- 

 somes ; 6, commencement of 

 axial filament. (After Moves.) 



FIG. 609. Cells of the 

 interstitial tissue of 

 the testis with crystal- 

 loid bodies. 



converted into spermatozoa. Every spermatid consists of a cell body 

 and a nucleus with a nucleolus. In the cell body near the nucleus 



