JKULC Or THt GAUGLTIC DOLPHIN 



CHAPTER XV : FRESH-WATER DOLPHINS. 



Susu or Gangetic Dolphin. Amazonian Dolphin or Boutu. 

 La Plata Dolphin. Chinese River Dolphin. 



(Family Platanistid^.) 



Four different kinds of dolphin, the Susu or Gangetic 

 Dolphin, the Boutu or Amazonian Dolphin, the La Plata 

 Dolphin and the Chinese River Dolphin are separated from 

 the Delphinidae because of lesser specialization of body struc- 

 ture ; they are more primitive cetaceans which approximate 

 closely in skeleton form to certain fossil dolphins. 



The skull is not so compressed from front to back as in the 

 higher whales so that the bones of a typical mammal are 

 somewhat more easily traceable. The neck vertebrae are of 

 considerable size and, as in the more primitive higher cetaceans, 

 are all separate from one another. Eight pairs of double- 

 headed ribs are usually found and the breast bone is well 

 developed. The flippers are short and broad. The Platanistids, 

 although in many features relatively so unspecialized, are 

 noteworthy for the unusual length and slenderness of upper 

 and lower jaws. 



Genus Platanista. 



THE SUSU OR GANGETIC DOLPHIN {Platanista 

 gangetica). Fig. 95. 



The Gangetic Dolphin attains an adult length of about 8 feet. 

 The snout and lower jaws are drawn out into a long forceps- 

 like beak, 7 or 8 inches long, behind which the wedge-shaped 



