URTNOGENITAL ORGANS 



TABULATED RESUME (Continued). 



449 



Anarunia. 



Amniota. 



A portion (except in Cyclo- 

 stomes, Teleosts and (?) Holo- 

 cephali) becomes related to the 

 testis and functional in the trans- 

 mission of the sperms, the distal 

 retaining its renal function. 



The anterior end becomes the 

 rete and vasa efferentia testis, 

 the caput epididymis, and per- 

 haps also the stalked hydatid 

 of Morgagni : the posterior end 

 becomes the paradidymis 

 (Giralde's organ). 



Persists as the kidney. 



The greater part of the an- 

 terior portion becomes the par- 

 ovarium, the posterior the paro- 

 ophoron. 



Serves in Teleosts merely as a 

 urinary duct. 



In Elasmobranchs, Ganoids, 

 Dipnoans, and Amphibians 

 serves as the urinogenital duct. 



Serves exclusively as the duct 

 of the mesonephros, i.e., the 

 urinary duct. 



The anterior portion becomes 

 the corpus and cauda epididymis 

 and the posterior the spermi- 

 duct (vas deferens). 



The greater part, as a rule, 

 degenerates ; the anterior por- 

 tion may be retained in a vestigial 

 form in the region of the par- 

 ovarium. In certain cases it 

 may persist, as a whole, as 

 Gartner's canal. The posterior 

 end becomes the organ of Weber. 



In Elasmobranchs it degene- 

 rates in post-embryonic life, 

 but vestiges of its anterior por- 

 tion are retained. Its existence 

 in most other Fishes is doubt- 

 ful. In Dipnoans and Amphi- 

 bians it is retained, at any rate 

 for some time, for its whole 

 length, in a functionless .and 

 often but little degenerate con- 

 dition. 



The anterior portion becomes 

 the unstalked hydatid of Mor- 

 gagni, the posterior, in some 

 Mammals, the so-called "uterus 

 masculinus " (prostatic vesicle). 

 In exceptional cases the whole is 

 retained as Rathke's duct. In 

 Sauropsida the posterior part 

 usually disappears. 



When present, gives rise to 

 the whole genital duct. 



Gives rise to the whole genital 

 duct. 



I 



Probably unrepresented. 



Arises in part (ureter and col- 

 lecting ducts) from the posterior 

 end of the mesonephric duct, and 

 in part (secreting elements) as a 

 caudal extension of the mesone- 

 phros. 



G G 



