URINOGENITAL ORGANS 



449 



TABULATED RESUME (Continued). 



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Anamnia. 



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. 



Persists as the kidney. 



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. 



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. 



When present, gives 

 the whole genital duct. 



rise to 



Amniota. 



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). 



The greater part of the an- 

 terior portion becomes the par- 

 ovarium, the posterior the paro- 

 ophoron. 



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. 



The anterior portion becomes 

 the unstalked hydatid of Mor- 

 gagni, the posterior, in some 

 Mammals, the so-called "uterus 

 masculiiius " (prostatic vesicle). 

 In exceptional cases the whole is 

 retained as Rathke's duct. In 

 Sauropsida the posterior part 

 usually disappears. 



Gives rise to the whole genital 

 duct. 



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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. 



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