626 REPRODUCTIVE ORGANS. 



days outside the body, and they are also very resistant to low 



temperatures. They appear at the 

 / , x time of puberty, and have been 



(WJl I V- a found in individuals ninety years 



:_ b of age, though they are not com- 



FIG. 404. Human spermatozoa. 

 The two at the left after Retzius; 

 the one at the extreme left is seen 

 in profile ; the others in surface view ; 

 the one at the right is drawn as de- 

 scribed by Jensen : a, head ; b, ter- 

 minal nodule; c, middle piece; d, 

 tail ; e, end-piece of Retzius (Bohm 

 and Davidoff). 



FIG. 405. Spermatozoa : a, human ; 6, of 

 the rat; c, of menobranchus (X 480). 



Epithelium. 

 Mucosa. 



Inner longi- 

 tudinal 

 muscular 

 layer. 



Middle cir- 

 cular mus- 

 cular layer. 



uter longi- 

 tudinal 

 muscular 

 layer. 



FIG. 406. Cross-section of vas deferens near the epididymis (human) (Huber), 



