546 APPENDIX. 



portion is of a conical figure, whose apex is placed 

 towards the centre of the kidney, the base mak- 

 ing the external surface ; each is composed of a 

 cortical and tubular substance, the tubular ter- 

 minating in the apex, which apex makes the ma- 

 milla. Each mamilla has an infundibulum, which 

 is long, and at its beginning wide, embracing the 

 base of the mamilla, and becoming smaller. The 

 whole kidney is an oblong flat body, broader and 

 thicker at the upper ei;d than the lower, and has 

 the appearance of being made up of different parts 

 placed close together, almost like the pavement 

 of a street. 



Whether being inhabitants of the water makes 

 such a construction of the kidney necessary I 

 cannot say ; yet one must suppose it to have some 

 connection with such a situation, since we find 

 it almost uniformly take place in animals inha- 

 biting the water, whether wholly, as this tribe, 

 or occasionally, as the Manatee, Seal, and white 

 Bear : there is however the same structure in the 

 black Bear, which, I believe, never inhabits the 

 water. This perhaps should be considered in 

 another light, as Nature keeping up to a certain 

 degree of uniformity in the structure of similar 

 animals ; for the black bear in construction of 

 parts is, in every other respect as well as this, like 

 the white bear. 



The capsulrc renales are small for the size of the 

 animal, when compared to the human, as indeed 

 they are in most animals. They are flat, and of an 

 oval figure : the right lies on the lower and pos- 



