118 MUSXELID^. 



subject of the specific identity, as there is a slight difference in the 

 colouring of the throat, and also a veiy great difference in the size 

 of the specimens. 



A careful examination and comparison of the specimen has satisfied 

 me that the Demerara and Surinam Otters are of the same species. 

 The specimen in Liverpool, from Demerara, is a very young animal, 

 with, its milk series of teeth. The tail of the Demerara specimen has 

 the same, marginal rib as the Surinam one; but in the preparation 

 it has been too much depressed on the sides, and the sides also are 

 artificially extended, giving it a fin-like appearance, which induced 

 me to give it the name of Pteronura. Oraspeclura, or margined- 

 taUed, would have been a much more appropriate one. The bones 

 have been almost entirely extracted from the skin of the feet, and 

 they have been evidently flattened by the stuffer. The size and 

 flatness of the feet in this specimen, which gave the animal so much 

 apparent relation to the Sea-Otters, do not exist in the unstuifed 

 specimen from Surinam, which has large feet, with very strong toes 

 united by a broad web extending to the end of the toes, and large 

 acute claws, the feet being quite of the normal or usual form of the 

 Otters', and having no more resemblance to those of the Sea-Otter or 

 Enhydns than is the case in any of the other species of the genus. 



The skull is very long and has sharply tubercular teeth, which 

 also shows that it is far removed from the very short, broad, square 

 skuU, with the very broad teeth with hemispherical tubercles, that is 

 so peculiar to the Sea-Otter. 



The Surinam specimen and the reexamination of the Demerara 

 specimen and its skull have enabled me to give a revised character 

 to the genus. 



Tribe III. ENHYDRINA. 



Head depressed. Hind feet large, elongate, rather fin-like, hairy 

 above and below, obliqvie, truncated ; the outer toes largest ; claws 

 small. Tail short, cylindrical. G-rinders broad, massive, flat- 

 topped. Flesh-tooth oblong, triangular, transverse ; inner side 

 narrow, tubercular : grinders similar, larger, outer edge narrow. 

 Marine. 



Enhydrina, Gray, P. Z. S. 1865, p. 135. 



18. ENHYDRIS. 



Tail short, cylindrical. Muzzle bald, oblong, triangular. Soles 

 entirely hairy, like the upper surface of the feet ; claws acute, small. 

 SkuU much dilated behind, and swoUen. Teeth 34; premolars 

 I . -I ; grinders very large, massive, flat-topped. 



Enhydra, Flemirui, Phil. Zool. 



Enhydris, Fischer, Si/n. Mamm. p. 228 ; Gray, Cat. Mamm. B. M. 

 xxi. p. 72; P. Z. S. 1865, p. 1.3.5, t. 



