212 Formation and use af Otter' s tail. Chapt. xv. 



"festival, the otter entered the temporary shed, walked 

 "across the floor, and came and lay down at my feet! 



"The specific name given by F. Cuvier is unfortunate, 

 "it being only the termination of the common native 

 "name Nir-nai, or water-dog, and wrongly spelled more- 

 "over. Blyth, in his catalogue, records a specimen from 

 Algeria, quite undistinguishable from specimens from 

 Bengal." 



The peculiar formation of the otter's tail is not with- 

 out interest. It is not round like that of a dog, cat or 

 rat, but flattened, and specially at the base where it is 

 three inches broad. It is flattened horizontally too as 

 in the Cetaceans (whales and porpoises &c), and not 

 perpendicularly as in true fish. Were it meant only for 

 a propeller in swimming it would have been most useful 

 had it been put on like a true fish's, but the advantage 

 of having it flattened horizontally is that the otter, like 

 the whale and the porpoise, is thereby enabled to come 

 rapidly to the surface for air. Ordinarily it is used like 

 the whale's tail or "flukes" to bring it to the surface 

 head foremost, but from Captain Salvin's letter above 

 quoted, it would seem that when the head of an otter *" 

 is forcibly kept down by a struggling fish, the tail of 

 the otter is still a power to bring the otter to the sur- 

 face tail foremost, and it is readily intelligible that 

 when holding on to a fleeing fish the otter can put on 

 a very heavy drag by simply curving its tail. On the 

 few occasions which I have as yet had of being near a 

 swimming otter, since I wished to observe it with this 



