786 DEVELOPMENT OF THE WOLFFIAN BODIES, ETC. 



A short distance above the internal organs of generation there com- 

 mences, on each side, a narrow tube which runs from above downward 



along the anterior border of the Wolffian body, 



Fig. 294. immediately in front of, and parallel with 



the excretory duct of this organ. The two 

 tubes then approach each other below ; and, 

 joining upon the median line, einpt}', together 

 with the ducts of the Wolffian bodies, into 

 the base of the allantois, or what will after- 

 ward be the urinary bladder. These tubes 

 serve as the excretory ducts of the internal 

 organs of generation ; and will afterward be- 

 come the vasa deferentia in the male, and 



INTERNAL ORGAN a OP ., . ,, . , . ,, ,, - 



GENERATION, in a foetal pig the Fallopian tubes m the female. Accord- 

 iy 2 centimetres long. From a i n g to Coste, the vasa deferentia at an early 



specimen in the author's pos- , -, .,, ., ,. -, 



session - 1, i. Kidneys. 2, 2. period are disconnected with the testicles ; 

 Wolffian bodies. 3,3 internal an d originate, like the Fallopian tubes, by 

 or^i > e f s ge r r uHnary t b S ild C der free extremities, presenting each an open 

 turned over in front. 5. intea- orifice. Afterward the vasa deferentia be- 

 come adherent to the testicles, and establish 



a communication with the tubuli seminiferi. In the female, the Fallo- 

 pian tubes remain permanently disconnected with the ovaries, except by 

 the edge of the fimbriated extremity ; which in many of the lower ani- 

 mals becomes closely adherent to the ovary, and envelops it more or 

 less completely in a distinct sac. 



Male Organs of Generation ; Descent of the Testicles. In the male 

 foetus there now commences a change of place in the internal organs 

 of generation, which is known as the u descent of the testicles." Jr. 

 consequence of this change, the testicles, which are at first placed 

 near the middle of the abdomen and in front of the kidneys, come at 

 last to be situated in the scrotum, outside and below the abdominal 

 cavity. They also become inclosed in a distinct serous sac, the tunica 

 vaginalis testis. This apparent movement of the testicles is accom- 

 plished in the same manner as that of the Wolffian bodies, namely, by 

 a disproportionate growth of the middle and upper portions of the 

 abdomen and of the tissues above the testicles, so that the relative 

 position of the organs becomes altered. 



By the upward enlargement of the kidneys, both the Wolffian bodies 

 and the testicles are soon found to occupy an inferior position. (Fig. 

 295.) At the same time, a slender rounded cord (not represented in the 

 figure) passes from the lower extremity of each testicle in an outward 

 and downward direction, crossing the vas deferens a short distance above 

 its union with its fellow of the opposite side. Below this point, the cord 

 spoken of continues to run obliquely outward and downward ; and, 

 passing through the abdominal walls at the situation of the inguinal 

 canal, is inserted into the subcutaneous tissue near the symphysis pubis. 

 The lower part of this cord becomes the gubernaculum testis. It con- 



