40O 



FISHES 



FIG. 230. Showing the principal modifications of the kidneys and reproductive organs 

 in Cyclostomes and Fishes. A, The pronephros and its duct in the embryo ; 

 B, the kidneys and genital pores in Petromyzon, the vestigial pronephros repre- 

 sented as in Myxine ; C and D, the urinogenital organs of a male and female 

 Elasmobranch ; E, of a male or female Teleost, or a male Lepidusteus ; F, of a 

 female Polypterus, Acipenser, Amia, or Osmerus. a, Anus ; a.d, archinephric 

 duct ; c, cloaca ; c.a, the coelomic aperture of the Mullerian duct ; c.p, cutaneous 

 pit ; g, gonad ; yd, gonoduct ; g.p, genital pore ; i, intestine ; m, Malpighian body ; 

 m.d, Miillerian duct ; inn, mesonephros ; mn l , vestigial mesonephros ; mn 2 , ex- 

 cretory portion of the mesonephros ("metanephros ") ; mn 3 , genital portion of meso- 

 nephros ; mn.d, mesonephric duct ; mtn. d, metanephric duct ; n, nephrostome ; 

 ov, ovary ; p.a, abdominal pore ; p.f, peritoneal funnel ; pn, pronephros ; pn', 

 vestigial pronephros ; s.g, shell gland ; s.s, sperm sac ; t, testis ; ug.s, u.s, urino- 

 genital sinus ; v.ef, vasa efferentia ; v.s, vesicula seminalis. 



