THE EXCRETORY ORGANS 



343 



one, the Wolffian (Leydig's) duct, remains connected with the 

 tubules of the mesonephros and forms its excretory canal. The 



Fig. 367. — Reconstruction of three somites of the Wolffian body (mesonephros) of 

 Hypogeophis, after Brauer. a, aorta; m^—m^, primary and secondary Malpighian bodies; 

 n^-n^, corresponding nephrostomes; s, tertiary segments of mesonephros; t^t,^, primary 

 and secondary mesonephric tubules; w, Wolffian duct. 





Fig, 368. — Diagrams of urogenital structures in (^4) indifferent and in female elas- 

 mobranchs and amphibians; {B) male elasmobranchs and amphibians; (C) male amniote 

 (mammal); {D) female amniote (mammal), b, urinary bladder; c, cloaca; e, epididymis; 

 k, kidney (metanephros);/, Fallopian tube; g, gonad; h, 'stalked hydatid'; /, longitudinal 

 tubule; m, MUllcrian duct (oviduct), rudimentary in li and C; mn, mesonephros; 0, 

 ovary; ol, ostium tubae abdominale; pd, paradidymis; po, paroophoron; pv, parovarium; 

 r, rectum; /, testis; m. uterus; ua, urethra; ur, ureter; va, vas aberrans; vd, vas deferens; w, 

 vasa efferentia; w, Wolffian duct, urinary in A, urogenital in B, genital in C andVudi- 

 mentary in D. 



Other, the Mullerian duct, is similarly related to the pronephros 

 and its derivatives and in the female forms the tube (oviduct) by 

 which the eggs are carried to the exterior. In other amphibia and 



