SPERMATOGENESIS— INSEMINATION 



169 



support and as a means of conveying nourishment to the growing 

 spermatozoa.'- The tails of the latter at this stage project 

 freely into the cavity of the tubule, and a little later the sper- 

 matozoa shift bodily forward and become completely Uberated. 



Fig. 42. — Section through portion of two seminiferous tubules in testis 



of rat. 



a, basement membrane ; b, spermatogonium ; c, spermatocyte ; d, sper- 

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



' Merkel, " Die Sliitzellen des Menschlichen Hodens," Muller's Archiv, 

 1871. Brov?n, "On Spermatogenesis in the Eat,'' Quar. Jour. Micr. Science, 

 vol. XXV., 1885- Bende, " Untersuohungen tiber den Ban den Funktioniren den 

 Samenkaualchens einiger Siiugethiere," Arch. f. Mih: Anat., vol. xxx., 

 1887. 



