REPRODUCTION 



347 



1^ ^i^.0^^:-% sie-i^ . 















?5^= ./ ^- '^5 ^■" :^;L 



Fig. G3. — Portion of two seminiferous tubules in testis of rat : a, base- 

 ment membrane ; b, spermatogonium ; c, spermatocyte ; d, sper- 

 matozoa in cavity of tubule ; e, interstitial tissue containing vessels 

 (Marshall). 



