MATURATION 



25 



Fig. 9. — Diagram showing cycle of phases in the spermatogenesis of the rat (Schafer, Brown). 

 The numbered segments of the circle represent portions of different seminiferous tubules, a, spermato- 

 gonia; a', sustentacular cells; b, spermatocytes actively dividing in 5; c, spermatids forming an irregular 

 clump in 1, 6, 7 and 8 and connected to sustentacular cell a' in 2, 3, 4 and 5. In 6, 7 and 8 advanced 

 spermatozoa of one generation are seen between spermatids of the next generation, s', parts of sperma- 

 tids which disappear when sperms are fully formed; s, seminal granules representing disintegration of s'; 

 a", in 1 and 2 are atrophied sustentacular cells. 



C E F 



Fig. 10. — Diagrams of the development of spermatozoa (after Meves in Lewis-Stohr) ; a.c, an- 

 terior centrosome; a./., axial filament; c.p., connecting piece; ch.p., chief piece; g.c, galea capitis; n, 

 nucleus; nk., neck; p., protoplasm; p.c, posterior centrosome. 



