1. iNiA. 227 



Inhab. Upper Peru or 'Bolivia, Eiver Moxos. Brazils, .Upper 

 Amaaons (Bates). Called Bouto. 



a, b. Skull of Bouto from Ega, from Mr. Bates : — 



° in. 



Length of skiill 21^ 



Length of beak 13^ 



Length of teeth-line, upper jaw 12| 



Length of teeth-line, lower jaw 11 



Length of lower jaw 171 



Length of symphysis of lower jaw 8i 



Width of skuU 10 



"Width in front of orbital notch 6 



Width at beak , 3 



Teeth f|-||.. The hinder eight or nine teeth only have a distinct 

 internal heel ; the succeeding ones gradually assume the usual conical 

 form, but all the teeth are more or less rugulose. 



The skuU m the Paris Museum, from D'Orbigny, has a prominent 

 tubercle behind the blowholes ; eyebrows convex and rugose on the 

 top ; beak with a slight groove on each side above ; lower jaw with 

 scarcely any ridge on the sides ; the symphysis long, occupying more 

 than half the length of the lower jaw ; teeth large, regular, hinder 

 ones with a rounded, regular tubercle on the inner side. 



in. 



Length of skull 19 



Length of beak 12 



Length of symphysis 9 



Length of teeth-line 11 



The Belphinus macrogenius (Fischer, Cuvier, Oss. Foss. v. 312. 

 t. 23. f. 4, 5, 9-11) appears to belong to this tribe. 



The following are the measurements of D'Orbigny's specimen, 

 from Bolivia, as given by M. F. Cuvier : — 



met. cent. 



Length, entire 2 4 



Length of muzzle 23 



Length to eye 34 



Length to blower 40 



Length to ears 43 



Length to pectoral fin 52 



Length to dorsal fin 1 30 



Length of pectoral 42 



Breadth of pectoral 18 



Breadth of caudal 50 



Height of dorsal 9 



Circumference of thickest part 1 4 



Belphinus Qeoffroyii was described from a specimen procured by 

 the French from the Lisbon Museum during their occupation of that 

 town, which the Portuguese most probably received from the Brazils. 

 I have examined the specimen, and it has the teeth of Inia. It is 

 covered with paint. It has no dorsal ; and it shows the teeth suffi- 



a2 



