14 



BULLETIN 36, UNITED STATES NATIONAL MUSEUM. 



bears the same number as this cranium {lUlb) and was figured as 

 belougiug with the latter (Trans. Zool. Soc., vi,pl. 4), in reality belongs to 

 a second and perfect cranium (1477fl), which, although not mentioned by 

 Sir Eichard Owen, was apparently received with the type. This last- 

 mentioned skull is wrongly labeled " No. 423. Type." A third skull (82 : 

 1, 2, 3) is also in the collection. In the Cambridge Zoological Museum 

 there is a fourth skull (573a) derived, according to the label, from 

 Wollongong. 



These four specimens agree well together; the Cambridge skull alone 

 presents any important differences. The differences observable in 

 tbis case relate to the comparative breadth of the skull and are very 

 probably sexual. The pterygoids in specimens 1477& (type) and 1477a 

 differ considerably in shape, but such variations are of frequent occur- 

 rence, and here at least, in my judgment, are not to be regarded as of 

 specific value. 



There are in the British Museum two stuffed skins of this species 

 which though smaller than Sir Eichard Owen's specimen agree well with 

 it in proi)ortions, except so far as regards the length of the pectoral fins. 

 The following measurements taken from these skins are in right lines, 

 except the distance from the extremity of the snout to the dorsal fin, in 

 measuring which the curve of the back was followed : 



Measurements of two mounted slcins of Sotalia gadarnu. 



Measurement. 



Total length 



Tip of beak to corner of nioutli 



Tip of beak to eye 



Tip o f beak to elevation of head 



Tip of beak to blowhole 



Tip of beak to anterior base of pectoral fin . 

 Tip of beak to anterior base of dorsal fin . . . 



Length of base of dorsal lin 



Height of dorsal fin (vertical) 



Length of pectoral fin (from anterior base). 



Breadth of flukes (tip to tip) 



Greatest breadt h of pectoral fin 



Teeth (about) , 



British Museum. 



No. 82 : 

 1, 2, 3. 



l7lch€S. 



63.0 



8.15 



9.6 



3.95 



10.30 



15.0 



28.0 



9.0 



5.5 



10.75 



16.75 



4.0 



No. 83 : 

 11, 20, 3. 



Inches. 

 62.75 



9.75 

 10.5 



4.0 

 10.75 

 16. 25 

 27.8 

 ?9. 



5.7 



12.4 

 3.65 



28-28 

 28-28 



S. gadarnu does not appear to be very closely related to the other 

 species of the genus. The differences which separate it from S. lentitji- 

 nofius will be considered in the section devoted to that species (p. IG). 

 From S. sinensis and the South American species it differs widely as re- 

 gards size of beak, number of teeth, etc., and the skeleton, when known, 

 will probably show that similar differences extend to other parts of the 

 body. 



The skull shows decided afifiuities to Tursiops, from some species of 

 which, were the pterygoids united, it would be very difficult to dis- 

 tinguish it. 



