64 

 Sub-order I. ODONTOCETE. 



Toothed Whales. 



Teeth always developed, but very variable in number and position ; 

 palate without baleen ; head of moderate or excessive size ; upper 

 surface of skull unsymmetrical ; external respiratory organ always 

 single ; gullet large ; rami of mandible nearly straight, invariably con- 

 nected anteriorly by a true symphysis ; sternum nearly always composed 

 of several pieces and united to several pairs of ribs by costo-aternal 

 ribs of unossified cartilage or of bone. 



(a) MEGAZOOPHAGA. Eapacious Whales. 



A. Teeth permanent, numerous, occupying nearly the whole length 

 of both jaws. 



Family I. PLATANISTID^). ' 



"Without dorsal fin, back slightly keeled ; cervical vertebrae free ; 

 head small, convex ; both jaws of nearly the same length and breadth ; 

 beak very long and narrow ; mandibular symphysis very long, more 

 than half the entire length of the rami, greatly resembling that of the 

 sperm whale ; sternum of one piece ; costo-sternal ribs cartilaginous ; 

 pectoral fin broad, truncated, five-fingered. 



Genus PLATAmsiA, 1 Pliny. 

 Teeth, If, or, 5= 112, or, 120. 



Rather stout, set well apart, subcylindrical, anterior ones longest, 

 compressed, and slightly curved ; posterior ones short, with occasionally 

 two short fangs. The long and slender beak, slightly more than three- 

 quarters of the entire length of the skull, is compressed at the sides, 

 expanded and slightly curved upwards at the extremitv, where it is 

 larger than in the middle. The black, shining eyes are exceedingly 

 minute, scarcely one-eighth of an inch in diameter, obviously better 

 adapted for turbid than clear waters. In general, their movements 

 appear to be sluggish, but when in pursuit of fish they become active 

 and fleet. There are but two species known, viz. : 



PLATAHTSTA GANGETICA, Eoxburg. Dolphin of the Ganges. 

 The Susu. 



Synonyms Delphinorhychus Gangeticus, Lesson. 



Platanista Gangeteca, Gray, B.M.C., 1866 ; Supp. 1871. 

 Soosoo of the Ganges. Jardine, Nat. Libr., vol. 7. 

 The Susu of the Ganges attains to about seven feet in length, and its 

 general colour is of a shining pearly grey. These animals frequent in 



1 ir\aravi(Tri)s t Pliny's name for a dolphin, considered by Cimer to be probably this 

 very species. 



