ORGANS OF REPKODUCTION. 



167 



The testicles are always paired, rounded, and situated in 

 the anterior part of the abdominal cavity, covered by the 

 liver. Vasa efferentia pass the semen into a much-convoluted 

 epididymis, which is continued into the vas deferens; this, 

 at the commencement of its course, is spirally wound, but 

 becomes straight behind, and has its end dilated into a 

 seminal reservoir. It opens with the urethra in a papUla 

 within the cloaca. 



The so-called claspers of Chondropterygians (Fig. 78) are 

 characteristic of all male individuals. They are semi-ossified 

 appendages of the pubic, with which they are movably joined, 

 and special muscles serve to regulate their movements. Some- 

 times they are armed with hook- 

 like osseous excrescences (Selache). 

 They are irregularly longitudinally 

 convoluted, and, when closely ad- 

 pressed to each other, form a canal 

 open at their extremity. A gland, 

 abundantly discharging a secre- 

 tion during the season of pro- 

 pagation, is situated at, and opens 

 into, the base of the canal. It is 

 still doubtful whether the generally- 

 adopted opinion that their func- 

 tion consists in holding the female 

 during copulation is correct, or 

 whether they are not rather an in- 

 tromittent organ, the canal of which 

 not only conducts the secretion of 

 their proper gland but also the 

 impregnating fluid. 



The ova of the oviparous Chon- 

 dropterygians are large and few in 

 number ; they are successively im- 



^> 



3) 



Fig. 79. — Egg of a Scyllium 

 from Magelhan's Straits (? Sc. 

 chilense). Natural size. 



