Genito -urinary Apjmrahis of the Male Porpoise. 115 



by the dorso-mesial and ventro-mesial borders. The greatest 

 thickness of the left kidney (dorso-mesial diameter) occurred 

 in association with this surface, but the right kidney was 

 thickest at a point external to this surface. The renal vessels 

 entered upon the mesial surface towards its anterior end, but 

 there was no distinct indentation or hilum. This surface 

 was further subdivided into two longitudinal areas or facets, 

 distinguished from each other by a slight longitudinal ridge. 

 Of these, the dorsal facet was concave, and indicated contact 

 relationship with the great abdominal vessels — aorta and 

 inferior vena cava — while the ventral facet was flat, and indi- 

 cated the mutual adaptation of the mesial surfaces of the two 

 kidneys. The peritoneal membrane did not occupy the 

 narrow chink between the two kidneys, but, as already stated, 

 this interval corresponded to the mesenteric base. In 

 possessing a mesial surface, the kidneys of this Cetacean 

 resemble those of other members of the group, but this is 

 not a character peculiar to Cetacea, as was supposed by 

 Hyrtl ^ and Daudt,^ for it has been shown that the human 

 kidney ^ has also a similar surface. It should be noted, 

 however, that the mesial surface of the human kidney results 

 from adaptation to the sides of the lumbar vertebrae by which 

 the two kidneys are separated from each other. 



The ventral or visceral surface of each kidney was convex 

 as a whole, but it presented depressed facets or impressions 

 corresponding to its visceral relationships. Neither of the 

 kidneys came into actual contact with the liver, for the 

 anterior end of the right one was from 3 to 4 cm. distant 

 from the nearest point in the dorsal margin of the right 

 lobe of the liver, while the distance between the left kidney 

 and the liver was about 10 cm. The anterior and outer part 

 of the ventral surface of the left kidney was considerably 

 indented, and thereby reduced in thickness, by the dorsal 

 aspect of the hinder end of the first compartment of the 

 stomach. The remainder of the ventral surface of the left 

 kidney, as well as the corresponding surface of the right 

 kidney, presented indentations corresponding to intestinal 



^ Hyrtl . . . quoted by - Daudt, loc. cit. 



^ Hepburu, Jour, of Anat. and Phya., vol. xxxiii. 



