X VISCERA 445 



hepatic and pancreatic ducts. The small intestine is narrow, 

 and is stowed away in a few irregular coils ; the rectum is wide ; 

 a caecum is absent. 



The cloaca is peculiar. The coprodaeum and urodaeum, cf. 

 p. 498, are confluent, and form a wide, oval bag, closed in front 

 and behind by strong sphincters, and it acts normally as a urinary 

 receptacle. In the dorsal wall open the two ureters ; a little 

 towards the sides, and ventrally, open the two oviducts, on the 

 right and left, near the base of the clitoris. Then follows a 

 transverse, soft, muscular fold, which shuts off this cavity from 

 the proctodaeum or outermost chamber. In the latter is 

 stowed away the rather large copulatory organ. It arises out of 

 the medio-ventral wall of the cloaca, and has a deep, longi- 

 tudinal groove on its morphologically dorsal side for the con- 

 duction of the sperma, the vasa deferentia opening near its 

 basal end. On either side of the root of this organ, in both 

 sexes alike, opens a peritoneal canal, wide enough in large 

 specimens to pass a goose-quill. The outer opening of the 

 cloaca forms a longitudinal slit ; within it, dorso-laterally, are 

 the openings of the two anal musk-glands. 



The kidneys are much lobed. The testes are long and oval ; 

 the ovaries are miich elongated and flat ; and the eggs con- 

 tained therein in great numbers are extremely small, except 

 those which ripen during the time of propagation. 



The vascular system has attained the highest state of 

 development of all reptiles. The heart is practically quadri- 

 locular, the partition between the right and left ventricle being 

 complete ; but there is still a small communication, the foramen 

 Panizzae, which lies in the middle of the wall common to both 

 aortae, where they leave their respective ventricles. The left 

 aortic arch conveys all the arterialised blood out of the left 

 ventricle, and supplies head, neck, trunk, and tail. The right 

 aortic arch, coming from the right ventricle, supplies venous 

 blood, mixed with what little arterial blood it receives through 

 the foramen Panizzae, to most of the viscera. On a level with 

 the stomach both descending aortic arches are still connected 

 with each other ; the left aorta supplies most of the gut ; the 

 right, the trunk and the kidneys. 



The outer ear lies in a recess, dorsally overhung by the 

 lateral edge of the bony squamoso-postfrontal bridge ; and this 



