OCR Text |
Show 1 i>04.] CIRCULATORY SYSTEM IX THE OPHIDIA. o65 gastric branches gives off two small branches to a couple of small glands which lie at the anterior end of the anteriorly situated testis. These glands resemble in a curious wTay the posteriorly lying spleen and pancreas, and show the same differences in colour. Contrary to what is usually found in snakes, and con-elated perhaps with the forward position of the testes, the first spermatic artery arises between the last gastric and the superior mesenteric. Arrived at the testis, which it reaches at about the end of the first quarter, the artery divides into an anterior and a posterior longitudinally running branch. The latter gives off shortly a slender and ventrally running branch to the peritoneal sheets envolving the portal vein &c. Further back, and just in front of the superior mesenteric, a dorsally running twig supplies what is, I presume, the mesorchium. Immediately after the superior mesenteric arises the second spermatic artery of this testis. The third spermatic arises a little farther on, close to the end of the testis, and between them arises, from the longitudinal testicular artery, a branch to the mesorchium. The third spermatic artery gives off before reaching the testis a branch en either side to the mesorchium. Between the two posterior spermatic arteries the adrenal portal vein lies, passing to the adrenal body from the parietes on the right side of the aorta. The left (posterior) testis has only two spermatic arteries, which lie, relatively speaking, in the same position as the second and third spermatic arteries of the right testis. The last of these gives off before reaching the testes a branch to the mesorchium, wThich is the only branch of the kind that I could find. Text-fig. 77. Posterior testis and blood-supply of Python spilotes. Lettering as in text-fig. 76. On the other hand, the longitudinal testicular artery gives off at least four slender branches, ventral in direction, which supply the fat-body. The most anterior of these joins a twig of the superior mesenteric which also supplies the fat-body. The superior mesenteric thus also contributes to the blood-supply of the testes. |