UROGENITAL SYSTEM. 323 
the longitudinal testicular canal of other vertebrates) which runs in 
the membrane (mesorchium) supporting the testis, back to the external 
opening, which is either directly to the exterior between the urinary 
opening and the anus (fig. 328) or into a urogenital sinus (fig. 321, B). 
This view is farther supported by the relations in the dipnoi. In 
Ceratodus there are numerous vasa efferentia which extend from the 
testis into the mesonephros. In Lepidosiren the efferent ductules are 
Fic. 325.—Diagrams of urogenital organs of male fishes, after Goodrich. A, Acipenser 
(Lepidosteus and Amia similar, but lack the oviduct); B, teleosts; C, Polypterus; D, Pro- 
topterus; E, urogenital openings of female salmon. uw, anus; apf, abdominal pore; cb, 
cloacal (‘urinary’) bladder; e, vasa efferentia; gp, genital pore (papilla); m, mesonephros; 
md, Miillerian(?) duct; 7, rectum; rc, renal corpuscle; s, urogenital sinus; ¢, testis; u, up, 
urinary pore; wgp, urogenital pore; v, vas deferens; w, Wolffian duct. 
fewer in number and they arise from a posterior degenerate portion 
of the testis, while in Protopterus (fig. 325, D) there is but a single 
vas efferens on either side and this passes through the posterior end 
of the Wolffian body. 
Oviducts.—In the elasmobranchs the Miillerian duct, which, as 
described above, arises by a splitting of the pronephric duct, serves 
as the oviduct. After separation from the Wolffian duct this opens 
in front into the coelom by means of the pronephric tubules and their 
