158 Dr. J. E. Gray on a new species of Dolphin. 



described from a specimen procured by the French from the 

 Lisbon Museum during their occupation of that town, and 

 which the Portuguese most probably received from the Brazils. 

 M. F. Cuvier, in his ^ Cetacea/ p. 112, described this species 

 under the name of Delphinus frontatus. 



M. D'Orbigny discovered the same, or at any rate a nearly 

 allied species, in the River Moxos in Upper Peru or Bolivia, 

 and described and figured it under the name of Inia Boliviensis, 

 Voy. Amer. Merid. t. 22. 



The measurements of the Brazilian skull are as follows, in 

 inches and parts of inches : — 



inches. 



Length of skull 2U 



ofbeak 13 



of teeth-line of upper jaw 12^ 



of lower jaw 11 



of lower jaw 17i 



of symphysis of lower jaw 8^ 



Width of skull 10 



in front of orbits at notch 6 



of beak at notch 3 



Teeth - - 

 lecin 26 27* ^ 



It is only the hinder eight or nine teeth which have a distinct 

 internal heel ; the succeeding ones gradually assume the usual 

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



Mr. H. W. Bates observes : " The animal from which the skull 

 was taken is very large, and wholly of a pinkish flesh-colour. I 

 have seen them rear themselves entirely above the surface of the 

 water when the sexes are sporting in shoaly bays. It goes in 



pairs, rolling together There are black dolphins of the 



larger species, but I do not know if a variety or a separate 

 species. They also roll in pairs, and are abundant towards the 

 Delta of the Amazon. I cannot say whether the flesh-coloured 

 species is found in the Delta ; one fact only I can mention — I 

 have never seen a black and a pink dolphin together in pairs. 

 They are always both either black or pink.^' — Letter, Feb. 17, 

 1856. 



The second species is named Tucuxi by the natives. Mr. H, 

 W. Bates has sent the skull of each sex. They are similar, but 

 the skull of the female is considerably smaller than that of the 

 male. These skulls evidently belong to a species of the genus 

 Steno, which has not before come under my observation. It 

 may be described in the Catalogues as 



Steno Tucuxi. The Tucuxi. 



Nose of the skull depressed at the base, convex and attenuated 

 at the tip, rather (yV^^) loiiger than the length of the head, 



