128 MORPHOLOGY OF THE ORGANS OF VERTEBRATES. 



less clearly traces of its double origin, as in cases of bicor- 

 nuate uteri. 



In the male the Miillerian duct almost entirely disappears, 

 a portion of its anterior end persisting as the stalked hydatid 

 (or hydatid of Morgnani), somewhat closely connected with the 



FIG. 135. Diagram of the modifications in the urogenital apparatus. A, in- 

 different and also the female ichthyopsidan ; B, male amphibian ; C, male amniote ; 

 D, female amniote. c, cloaca; e, epididymis ; /, fimbriated extremity of Fallopian 

 tube; g, gonad; h, stalked hydatid; /', kidney (metanephros) ; ///, Miillerian duct; 

 mn, mesonephros (Wolffian body); o, ovary; od, oviduct; of, ostium tubge ; pd, 

 paradidymis; po, paroophoron ; pv, parovarium ; r, rete ; /, testes ; u, uterus; ;;/, 

 uterus masculinus; ur, ureter; va, vas aberrans; vd, vas deferens; ve, vasa effer- 

 entia; ?u, Wolffian duct. 



epididymis (see below), while the posterior end occasionally 

 retains its lumen, and is known as the uterus masculinus. 



The history of the Wolffian duct is somewhat different. In 

 the female its anterior end degenerates ; and in the amniotes, 

 where the metanephros usurps the functions of the mesone- 

 phros, this degeneration extends to the whole tube. The only 

 portions which persist are, a rudimentary structur behind 



