400 FISHES CHAP. 
Ug.s 
Fra. 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 Myzxine; C and D, the urinogenital organs of a male and female 
Elasmobranch ; E, of a male or female Teleost, or a male Lepidosteus; F, of a 
female Polypterus, Acipenser, Amia, or Osmerus. a, Anus; @.d, archinephric 
duct ; ¢, cloaca; c.a, the coelomic aperture of the Miillerian duct ; c.p, cutaneous 
pit ; g, gonad ; gd, gonoduct ; g.p, genital pore ; 7, intestine ; m, Malpighian body ; 
m.d, Miillerian duct ; mn, mesonephros ; mn}, vestigial mesonephros ; mn”, ex- 
cretory portion of the mesonephros (“ metanephros’’) ; mn*, genital portion of meso- 
nephros ; mn.d, mesonephric duct; mtn.d, metanephric duct; , nephrostome ; 
ov, Ovary; p.a, abdominal pore ; p.f, peritoneal funnel ; pn, pronephros ; pn’, 
vestigial pronephros ; s.g, shell gland; s.s, sperm sac; ¢, testis; ug.s, w.s, urino- 
genital sinus ; v.ef, vasa efferentia ; v.s, vesicula seminalis. 
