SPERMATOGENESIS INSEMINATION 



169 



support and as a means of conveying nourishment to the growing 

 spermatozoa. 1 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 liberated. 



FIG. 42. Section through portion of two seminiferous tubules in testis 



of rat. 



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

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



1 Merkel, " Die Stiitzellen des Menschlicben Hodens," Muller's Archii; 

 1871. Brown, "On Spermatogenesis in the Rat," Quar. Jour. Micr. Science, 

 vol. xxv., 1885. Bende, " Untersuchungen iiber den Bau den Funktioniren den 

 Sarnenkanalchens einiger Saugethiere," Arch. f. Mikr. Anat., vol. xxx., 



1887. 



