64 DR. J. K. GRAY ON PTERONURA SANDBACHII. [Jaii. 23, 



The Liverpool specimen has remained unique up to this time, and 

 Pteronura was the only well-establislied genus of Mammalia wanting 

 in the British-Museum Collection. 



In the latter end of 1867 the British Museum received from Dr. 

 Krauss the skins of a large female Otter and its cub, under the name 

 of Lutra brasilietisis, which had been obtained in Surinam by Mr. 

 Kappler. 



As I had lately published a monograph of Mustelidce, including 

 the species ol LutrincB, in the ' Proceedings of the Zoological Society ' 

 for 1865, these specimens were entered in the register, and put away 

 for future examination. But the skin which Mr. Bartlett exhibited 

 at the last Meeting having excited new interest as regards the spe- 

 cimens of Otters, the skins in store were examined, and it was soon 

 seen that the Otter from Surinam was not the true Lutra Irasili- 

 ensis, and was very nearly allied to, if not the same species as, the skin 

 that Mr. Bartlett had exhibited. Tlie s[)ecimen chiefly differs from 

 Mr. Bartlett's skin in the tail being thick and strong, and convex 

 on the upper and lower surface, nearly as in other Otters ; so that 

 the flatness of the u])per and under surface of the prepared skin 

 was doubtless produced by the })reparation or dressing of it ; and 

 it was this excessive flatness that gave the tail such an artificial 

 apjiearance. I believe that the tail of a Common Otter {L. vulgaris) 

 might artificially be made to resemble the tail of tliat prepared skin. 

 That there was considerable cause for scepticism I think is ])roved 

 by the experiment that Mr. Bartlett himself made to see if the cord- 

 like margins on the side of the tail were not artificially made, and 

 would disappear in soaking and stretching. 



As soon as 1 discovered the Surinam Otter I thought it ought to 

 be compared with the one from Demerara. I therefore wrote to the 

 Secretary of the Royal Institution of Liver})ool to request that they 

 would allow the specimen, which I originally described, to be sent 

 to the Museum for me to examine it, and show it to the Zoological 

 Society. He, most kindly and liberally, immediately granted my 

 request, and, on a second aj)plication, allowed me to extract the 

 skull of the specimen, in order that there might be no doubt on the 

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

 colouring of the throat, and also a very 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 n.ilk series of teeth. The tail of the Demerara specinjcn has 

 the same marginal ribs as the Surinam one ; but in the preparation 

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

 iirlificially extended, giving it a fin like appearance, which induced 

 me to give it the name ot Pteronura. Qraspedura, or margined- 

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

 liave been almost entirely extracted from the skin of the feel, and 

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

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



