EXCRETORY AND REPRODUCTIVE SYSTEMS. 547 
The segmental duct of each side divides into Wolffian 
and Miillerian ducts. The Wolffian duct becomes in the 
male the vas deferens, in the female it is an unimportant 
Wolffian duct; the Miillerian duct becomes in the female 
the oviduct, in the male it is a mere rudiment. 
The muscles and other organs of Elasmobranchs retain 
considerable quantities of nitrogenous waste products. 
There can be no doubt 
that the body cavity helps 
in excretion, and gets rid 
of waste through the two 
abdominal pores. In some 
Elasmobranchs these are 
replaced by openings (neph- 
rostomes) into the kidney. 
Occasionally there are both 
nephrostomes and abdomi- 
nal pores. 
pon ae 
The male organs or 
testes lie on each side 
of the cardinal sinus, 
moored by a fold of, 
peritoneum. Sperma- 
tozoa pass from the 
testis by vasa effer- 
entia into a tube sur- 
rounded anteriorly by 
epididymis. The tube 
of the epididymis is 
continued into the F!G. 289.—Urogenital organs. of female 
vas deferens, which bee nee A nee page 
a . : @g., Aperture of united oviducts; W.D, olffan 
is dilated posteriorly “uct; ov, ovary; O.D.G., oviducal gland ; 
info @ seminal vee ai. Sivan deter ied 
icle and an adjacent kidney (arrow from base of oviduct into cloaca). 
sperm - sac. Finally, ; 
the two vasa deferentia open into the urogenital sinus, 
whence the spermatozoa pass into the cloaca. Thence, in 
copulation, they pass into the complex “claspers”.of the 
male, which are said to be inserted into. the cloaca of the 
female.. 
The female organs or ovaries lie on each side of the car- 
$99 7» 2 2.2. 
