382 THE AMAZONIAN DOLPHIN CHAP. 



those of terrestrial mammals ; i.e. the humerus is distinctly the 

 longer, the converse usually obtaining among Whales. But 

 Plata nista again agrees with Inia. The teeth are remarkable 

 for the fact that the hindermost ones of the series have an 

 additional lobe ; they are not purely conical as are those of 

 Whales generally. 



There is but one species, Inia yeoffrensis, which inhabits the 

 Amazons, and grows to a length of 8 feet. Its colour 

 variations are rather extraordinary, unless they can be set down 

 to sex, which has been denied. Some individuals are wholly 

 pink ; others are black above and pink beneath. This Whale is 

 believed by the Indians to attack a man in the water, and it is 

 added that the Sotalia of the same streams will defend him from 

 these attacks ! Naturally, therefore, superstitious reverence 

 attaches to this Dolphin, which is tiresome to the naturalist who 

 wants specimens, as Professor Louis Agassiz found. 



In the genus Pontoporia l the dorsal fin is well developed 

 and falcate. The teeth are very numerous, 200 in all. The 

 ribs articulate as in Dolphins. The skull closely resembles that 

 of Inia, and the scapula is, as in that genus, " normal." 



The proper name for Pontoporia is really Stenodelphis, which 

 name was first used by Gervais a month or two before Gray, who 

 separated it from the vague Delpkinus of its original discoverer, 

 Gervais himself. It has a longer snout than Inia, which, being 

 bent towards the extremity in a downward direction, curiously 

 suggests the skull of a Curlew. In details, however, the skull is 

 exceedingly like that of Inia. It is nearly symmetrical. The 

 vertebral formula appears to be the following: C 7, D 10, L 5, 

 Ca 20 = 42, just one over the number of the vertebrae in 

 Inia. The sternum is in two pieces. Of the ten pairs of 

 ribs the first three are double-headed. These and the next have 

 sternal moieties joining the sternum, of which the first three are 

 ossified, the last being apparently merely a ligament. 



There is a single species of the genus, P. Uainvillii. This 

 Whale is described by Mr. Lydekker as being of a clear brown 

 colour, harmonising with the waters of the estuary of the 

 Amazons and the La Plata which it inhabits. The same colour 

 characterises Sotalia pallida of those parts of the world, and 



1 Flower, Trans. Zool. Soc. vi. 1867, p. 106 ; and Burmeister, Proc. Zool. Soc. 

 1867, p. 484. 



