232 



Basic Structure of Vertebrates 



BV- 



4 





Fig. 195. Cross sections of testis tubules of a mouse. (BV) Blood-vessel; (F) 

 fat granules; (IC) interstitial cells; (S 1 ) spermatogonia; (S 2 ) spermatocytes; (S 3 ) 

 spermatids; (SP) spermatozoa; (ST) sustentacular cells. (X 360.) (Modified from 

 Bremer: "Text-Book of Histology," Philadelphia, The Blakiston Company.) 



VESICULAR FOLLICLE. 

 OVUMv 



'PRIMARY FOLLICLE 



NUCLEUS| 



OVUM. 







FOLLICULAR ^v^.'.'/- •.,'.,, ,.'V;.- . - sj<-:1^ ' 



CELLS ' '- -■>. ..'.•; "?\<T£Z&%- 



Fig. 196. Section through cortical region of the ovary of a mouse showing young 

 (primary) ovarian follicles and older (vesicular) follicles. (X 76.) (Courtesy, Neal 

 and Band: "Comparative Anatomy," Philadelphia, The Blakiston Company.) 



