EXCRETORY ORGANS. 725 



The latter, i.e. the anterior part, is first absorbed ; and in some 

 Reptilia the posterior part, extending from the region of the genital 

 glands to the permanent kidney, persists till into the second year. 



Various remnants of the Wolffian body are found in the adults of both 

 sexes in different types. The most constant of them is perhaps the part in 

 the female equivalent to the head of the epididymis and to parts also of the 

 coiled tube of the epididymis, which may be called, with Waldeyer, the 

 epoophoron 1 . This is found in Reptiles, Birds and Mammals ; though in a 

 very rudimentary form in the first-named group. Remnants of the anterior 

 non-sexual part of the Wolffian bodies have been called by Waldeyer 

 parepididymis in the male, and paroophoron in the female. Such remnants 

 are not (Braun) found in Reptilia, but are stated to be found in both male 

 and female Birds, as a small organ consisting of blindly ending tubes with 

 yellow pigment. In some male Mammals (including Man) a parepididymis 

 is found on the upper side of the testis. It is usually known as the organ of 

 Giraldes. 



The Mlillerian duct forms, as has been stated, the oviduct in 

 the female. The two ducts originally open independently into 

 the cloaca, but in the Mammalia a subsequent modification of 

 this arrangement occurs, which is dealt with in a separate 

 section. In Birds the right oviduct atrophies, a vestige being 

 sometimes left. In the male the Miillerian ducts atrophy more 

 or less completely. 



In most Reptiles and in Birds the atrophy of the Miillerian ducts is 

 complete in the male, but in Lacerta and Anguis a rudiment of the anterior 

 part has been detected by Leydig as a convoluted canal. In the Rabbit 

 (Kolliker) 2 and probably other Mammals the whole of the ducts probably 

 disappears, but in some Mammals, e.g. Man, the lower fused ends of the 

 Miillerian ducts give rise to a pocket opening into the urethra, known as the 

 uterus masculinus ; and in other cases, e.g. the Beaver and the Ass, the 

 rudiments are more considerable, and may be continued into horns homolo- 

 gous with the horns of the uterus (Weber). 



The hydatid of Morgani in the male is supposed (Waldeyer) to represent 

 the abdominal opening of the Fallopian tube in the female, and therefore to 

 be a remnant of the Miillerian duct. 



Changes in the lower parts of the urinogenital ducts in the Amniota. 



The genital cord. In the Monodelphia the lower part of 

 the Wolffian ducts becomes enveloped in both sexes in a special 



1 This is also called parovarium (His), and Rosenmiiller's organ. 



2 Weber (No. 553) states that a uterus masculinus is present in the Rabbit, but 

 his account is by no means satisfactory, and its presence is distinctly denied by 

 Kolliker. 



