DEVELOPMENT OF THE GENITO-URINARY APPARATUS. 831 



called the duct of the Wolffian body. This finally disappears in the female, 



but it is developed into the vas deferens in the male. The other duct, which 



is external to the duct of the Wolffian body, disappears in the male, but it 



becomes the Fallopian tube in the female. This is 



known as the duct of Miiller. Behind the Wolffian 



bodies, are developed the kidneys and the suprarenal 



capsules. 



As the development of the Wolffian bodies attains 

 its maximum their structure becomes somewhat com- 

 plex. From their proper ducts, which are applied di- 

 rectly to their outer borders, tubes make their appear- 

 ance at right angles to the ducts, which extend into the 

 substance of the bodies and become somewhat convo- 

 luted at their extremities. These tubes communicate ^red^yD ) ait<S en pre " 

 directly with the ducts, and the ducts themselves open L heart ; 2, anterior ex- 



r tremity ; 3, posterior 



into the lower part of the intestinal canal, opposite to extremity ; 4, woman 

 the point of its communication with the allantois. The abdominal walls have 



x . been cut away, in order 



The tubes of the Wolffian bodies are simple, termma- to show the position of 



' the Wolffian bodies. 



ting in single, somewhat dilated, blind extremities, are 

 lined with epithelium, and are penetrated at their extremities, by blood-ves- 

 sels, which form coils or convolutions in their interior. These are undoubt- 

 edly organs of depuration for the embryon and take on the office to be after- 

 ward assumed by the kidneys ; but in the female they are temporary struct- 

 ures, disappearing as development advances, and having nothing to do with 

 the development of the true, urinary organs. 



The testicles or ovaries are developed at the internal and anterior surface 

 of the Wolffian bodies, first appearing in the form of small, ovoid masses. 

 Beginning just above and passing along the external borders of the Wolffian 

 bodies, are the tubes called the ducts of Miiller. These at first open into the 

 intestine, near the point of entrance of the Wolffian ducts. In the female 

 their upper extremities remain free, except the single fimbria which is con- 

 nected with the ovary. Their inferior extremities unite with each other, 

 and at their point of union they form the uterus. When this union is in- 

 complete there is the malformation known as double uterus, which may be 

 associated with a double vagina. The Wolffian bodies and their ducts disap- 

 pear, in the female, at about the fiftieth day. A portion of their structure, 

 however, persists in the form of a collection of closed tubes constituting the 

 parovarium, or organ of Rosenmliller. 



In the female the ovaries pass down no farther than the pelvic cavity ; 

 but the testicles, which are at first in the abdomen of the male, finally de- 

 scend into the scrotum. As the testicles descend they carry with them the 

 Wolffian duct, that portion of the Wolffian body which is permanent consti- 

 tuting the head of the epididymis. At the same time a cord appears, at- 

 tached to the lower extremity of the testicle and extending to the symphysis 

 pubis. This is called the gubernaculum testis. It is at first muscular, but 

 the muscular fibres disappear during the later periods of utero-gestation. It 



