65 



great numbers the slow-moving labyrinths of the rivers and creeks 

 which intersect the delta of the Ganges, but they are also known to 

 have ascended that river to more than a thousand miles above Calcutta. 

 They, however, confine their limits of range to within the bounds of 

 rivers, never venturing out into the open ocean. 



PLATAKISTA IITDI, Blyth. The Susu of the Indus. 

 Synonyms Platanista Gangetica (minor), Owen. Cat. Coll. Surg. 



Platanista Indi, Blyth. Journ. Asiat. Soc., Bengal: Gray, 



B.M.C., 1866 ; Suppl., 1871, p. 62. 



As the name implies, this dolphin inhabits the river Indus and its 

 tributaries, and in colour, size, and habits, bears a great resemblance to 

 the species first described ; it differs, however, in possessing a larger and 

 more robust skull, and in the teeth, although equal in number, being 

 shorter, and more ground down by attrition. 



Genus iNiA. 1 , Gray. 

 Teeth, gg to |H = 104 to 132. 



Conical, permanent, firmly set, with compressed roots ; anterior ones 

 simple, sharp, slightly incurved ; posterior with a broad, rounded 

 tubercle towards the base of the crown ; beak of the skull three- 

 quarters of the entire length of the skull ; pectoral fin large, ovate, 

 obtusely pointed. The lower jaw, being terminated by a long cylindrical 

 muzzle, affords, like the Platanista, an exact miniature resemblance to 

 that of the Cachalot. 



INIA GEOFFEOTENSIS, de Blainville. The Inia. 

 Synonyms Delphinus Geoffroyii, Desm. ; Mamm. 

 DelphinorTiynchus frontatus. F. Cuvier. 

 Inia Boliviensis, D'Orbigny. Voy. Amer. Merid. 

 Inia Geoffroyii, Gray, B.M.C., 1866. Suppl., 1871, p. 64. 

 Inia Geoffroyensis, Flower ; Tran. Z. Soc., vol. 6, part 3. 

 This animal is at the present the only one of the genus, but from the 

 great variation in the number of the teeth, 2 presented by several skulls 

 in European museums, the probability arises that more than one kind 

 will hereafter be distinctly determined. 



The female Inia Geoffroyensis, when adult, measures about 7 feet ; 

 the male, it is said, arrives to a much larger size ; the colour of both is 

 of a pale blue on the upper portions of the body, and reddish under- 

 neath. 



This dolphin is a native of South America, and, in groups of three or 

 four, locates not only the remote tributaries of the Amazon, but, at vast 

 distances from the sea, the elevated lakes of Peru, and thus may be 

 considered as a true fresh-water cetacean. 



1 Inia, so named by the native Indians of Bolivia. 



2 On this point see Gray, Suppl., p. 64, and Flower T. Z. S-, vol. 6, p. 87. 



P 



