SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



Orinoco and the present animal in the Yangtze. The Chinese river- 

 dolphin may be named and described as follows : 



LIPOTES, gen. nov. (Iniidae) 



Type. — Lipotes vexillifer, sp. nov. 



Diagnosis. — General structure of skull as in Inia, but beak bowed 

 upward, basicranial axis not conspicuously bent downward from 

 axis of beak, proximal extremity of intermaxillary thin and plate- 

 like, not forming- a raised anterior border to narial aperture, mandib- 

 ular symphysis barely equal to free portion of ramus ; teeth about 

 130, essentially uniform throughout the toothrow, the form of the 

 crown and character of the enamel-wrinkling much as in the median 

 teeth of Inia, but root not thickened, the entire tooth resembling that 

 of the Miocene North American " Schisodelphis" ; dorsal fin large,, 

 triangular. 



Skull. — While the skull (plates 2, 4, 6, 8, 9) presents more features 

 of likeness to that of Inia (plates 3, 5, 7, 8, 10) than to that of any 

 other known cetacean, there are obvious dififerences between the 

 South American and Chinese river-dolphins in all the details of 

 cranial structure. The more important of these have been mentioned. 

 Among the others the following seem worthy of note : 



Dorsal Aspect 

 (Plates 2 and 3) 

 Lipotes 

 Narial aperture slit-like in front. 



Inia 



Maxillarj' crest nearly horizontal 

 over temporal fossa, strongly benl 

 upward over orbit. 



Area between lambdoid crests 

 wider than high. 



Breadth across maxillary crests 

 through posterior border of narial 

 opening slightly greater than inter- 

 orbital breadth. 



Region between crest and nares 

 slightly concave. 



Intermaxillary convex laterally in 

 front, concave behind toothrow. 



Protuberance behind nares smaller 

 than narial openings. 



Nasals broader than high, not over- 

 hung by frontals. 



Entire condyles visible when skull 

 is viewed from directly above. 



Narial aperture broadly rounded in 

 front. 



Maxillary crest essentially in one 

 plane throughout. 



Area between lambdoid crests 

 higher than wide. 



Breadth across maxillarj' crests 

 through posterior border of narial 

 opening much less than interorbital 

 breadth. 



Region between crest and nares 

 deeply concave. 



Intermaxillary convex laterally 

 throughout. 



Protuberance behind nares larger 

 tlian narial openings. 



Nasals higher than broad, over- 

 hung by frontals. 



Condyles hidden when skull is 

 viewed from directlv above. 



