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descent of tlie testicles into the scrotum is effected are not fully and 

 exactly known. It was formerly believed that a membraneous and partly 

 muscular cord, called the gubernaculum testis, which extends while the 

 testicle is yet high in the abdomen, from its lower part, through the 

 abdominal wall (in the situation of the inguinal canal) to the front of 

 the pubes and lower part of the scrotum, was the agent by the contraction 

 of which the descent was effected. It is now generally thought, how- 

 ever, that such is not the case, and that the descent of the testicle and 

 ovary is rather the result of a general process of development in these 

 and neighboring parts, the tendency of which is to produce this change 

 in the relative position of these organs. In other words, the descent is 

 not the result of a mere mechanical action, by which the organ is dragged 

 down to a lower position, but rather one change out of many which 

 attend the gradual development and re-arrangement of these organs. 

 It may be repeated, however, that the details of the process by which 

 the descent of the testicle into the scrotum is affected are not accurately 

 known. 



The homologue, in the female, of the gubernaculum testis is a 

 structure called the round ligament of the uterus, which extends through 

 the inguinal canal, from the outer and upper part of the uterus to the 

 subcutaneous tissue in front of the symphysis pubis. 



At a very early stage of foetal life, the Wolffian ducts, ureters, and 

 Miillerian ducts, open into a receptacle formed by the lower end of the 

 allantois, or rudimentary bladder ; and as this communicates with the 

 lower extremity of the intestine, there is for the time, a common recep- 

 tacle or cloaca for all these parts, which opens to the exterior of the 

 body through a part corresponding with the future anus, an arrange- 

 ment which is permanent in reptiles, birds, and some of the lower mam- 

 malia. In the human foetus, however, the intestinal portion of the 

 cloaca is cut off from that which belongs to the urinary and generative 

 organs; a separate passage or canal to the exterior of the body, belong- 

 ing to these parts, being called the sinus uro-genitalis. Subsequently, 

 this canal is divided, by a process of division extending from before 

 backward or from above downward, into a 'pars urinaria' and a 'pars 

 genitalis. ' The former, continuous with the urachus, is converted into 

 the urinary bladder. 



The Fallopian tubes, the uterus, and the vagina are developed from 

 the Miillerian ducts (fig. 516, m), whose first appearance has been al- 

 ready described. The two Miillerian ducts are united below into a sin- 

 gle cord, called the genital cord, and from this are developed the vagina, 

 as well as the cervix and the lower portion of the body of the uterus ; 

 while the ununited portion of the duct on each side forms the upper 

 part of the uterus, and the Fallopian tube. In certain cases of arrested 



