URINOGENITAL ORGANS 



365 



prolonged backwards into ducts which join and open to the exterior, 

 or open into the base of the urinary ducts (Figs. 354, 356, B). 



A few Teleosts have free ovaries which shed the ova into the 

 coelom in the normal manner. In these cases the ova are carried 

 out either by oviducts of considerable length (Osmerus) or very 

 short (other Salmonidae) (Fig. 355, E), or again they may pass out 

 by mere pores representing the last stage of degeneration of the 

 oviduct (Anguillidae, Galaxiidae, Notopteridae, Hyodontidae, Osteo- 

 glossidae, and Misgurnus, a Cyprinid) (Hyrtl [232a], Rathke [342], 

 MacLeod [288]). 



The opening of the genital ducts to the exterior varies much in 



bl 



9° 



Fig. 354. 



Left-side view of a dissection of a male Esox Indus, I.., showing the median apertures of 

 the rectum, genital ducts, and kidney ducts, a, anus ; a.b, air-bladder, blind hinder end ; ao, 

 dorsal aorta ; bl, urinary bladder ; cv, gd, vas deferens ; g.o, genital opening ; /', intestine ; /.', 

 kidney (meson ephros) ; m.d, mesonephric duct ; p.c, posterior cardinal ; t, testis ; u.o, 

 urinary opening. 



position among the Teleostei. As a rule, the oviducts or pores open 

 by a median aperture between the anus and the urinary pore (Fig. 

 354, 356, E). The cloaca has been lost, though traces of it may 

 perhaps be seen in some lower forms. The sperm-ducts may open 

 into the base of the mesonephric ducts or bladder, as in Eels, 

 Anableps, Perca, Zoarces, Cydopterus, etc. ; or by a special opening, 

 Clupea, Scarus, Trigla, Tinea, etc. ; or together with the anus, Lota ; 

 or with both the anus and the kidney, Lophobranchii (Hyrtl, 

 Stannius [417]). 



The urinogenital organs of the Teleostei present features which 

 are very difficult to explain and have given rise to much contro- 

 versy (Rathke [342], Huxley [231], Waldeyer [478], Semper [404], 

 Balfour [29, 30], Brock [59, 60], Weber [482], Jungersen [253],. 



