400 JOHN LEWIS BREMER 



one ovarian artery is a branch of the mesenteric artery. I find 

 here, then the same grouping of animals that occurred when the 

 time of junction of rete cords and testis cords was under consider- 

 ation; species with large Wolffian bodies (so far as my limited 

 studies show) provide a new vessel for the genital glands, while 

 those with small Wolffian bodies utilize branches from the nearest 

 arteries. 



In man and cat the mesonephric arteries anastomose freely 

 with each other before entering the glomeruli, and with the early 

 degeneration of the glomeruli the number of mesonephric arteries 

 diminishes gradually, until one only is left; this one is, however, 

 connected with all the arteries of the testis, and so becomes the 

 single spermatic artery. The factors in this decrease in number of 

 the Wolffian arteries seem to be the descent of the testis, which 

 stretches them into long parallel vessels, and the ingrowth of the 

 cords which are to form the cortex of the suprarenal body, which 

 occurs directly in the course of these vessels, and presses upon 

 them. Incidentally it may be mentioned that small pieces of 

 this suprarenal tissue are often carried down with the lengthening 

 arteries, and left as the small aberrant glands not infrequently 

 found on the posterior wall of the abdominal cavity, along the 

 course of the spermatic artery. In a human embryo of 37.0 

 mm. (H. E. C, no. 820) there are two complete spermatic arteries 

 in each side, and four or five arterial stems parallel to the main 

 arteries either joining them or ending blindly, evidently recently 

 obliterated. In an embryo of 44.3 mm. (H. E. C, no. 293) one 

 artery on each side remains, with two or three obliterated pieces 

 beside it. In both embryos suprarenal tissue appears along the 

 course of the arteries. This method of arriving at a single sperm- 

 atic artery on each side in man accounts for the wide range in its 

 point of origin in the adult, as described in the text-books of anat- 

 omy. 



The veins of the testis in all the mammals examined arise as 

 simple offshoots from the sinusoids of the Wolffian body in the 

 neighborhood of the genital gland. 



The blood vessels of the testis in man, then, arise as two capil- 

 lary networks, one from the branches of the efferent arteries of the 



