228 DELPHINID^. 



ciently to exhibit their rugose state, and the large and peculiar 

 tiibcrcle on the inner side of tlie hinder ones, which is characteristic 

 of this genus, and which was observed by M. Desmarest, who de- 

 scribes them as " coniques, obtuses, avec une sorte de collet infe- 

 rieurement, et entre leur svirface est rugueuse." 



M. Cuvier (Oss. Foss. v. 278) describes the Lisbon specimen under 

 the name of D. frontatus, but his character for that species is taken 

 from a skull of the genus Steno, instead of from the teeth in the 

 specimen from Lisbon ; he also observes that it is not impossible that 

 the Masouen blanc oi Duhamel (Peches, ii. 1. 10. f. 4), received from 

 Canada, may not be a bad representation of the animal. Hence M. de 

 Blainville's idea of the Canadian habitat. The Masouen blanc of 

 Canada is certainly a Belw/a, very erroneously represented. 



M. F. Cuvier, in his ' Cetacea,' p. 121, describes this specimen 

 under the name of D. frontatus. 



The Bouto is found near Ega. "The animal 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. They go in pairs, rolling together. There are black 

 dolphins of a 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 Amazons. 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 either black or ^vak.'"— Bates, 17 Feb. 1856 ; Ann. Sf Mag. 

 N. H. 1856, xviii. 158. 



This animal inhabits " the upper parts and the branches of the 

 great river Amazons, to the Indians living on the borders of which 

 it is a creature of no small value. It was described by D'Orbigny 

 as the type of a new genus under the name of Ima BoUviensis, by 

 which it has since been generally known ; but it appears to have 

 heen previously described by Spix and Martins under the name of 

 Delphinus Amazonicus ; while, according to M. Paul Gervais, it is 

 identical with the D. Geoffrensis of De Blainville, who, however, 

 supposed that his specimen came from Canada." — Comptes Rendus, 

 April 58, 1856, 806; Ann. ^ Mag. N. H. xyii. 522. 



FamUy 6. DELPHINID^. 



Head beaked ; beak bald, or with only a few whiskers. Nostril 

 united into a transverse blower on crown of head. Teeth in the 

 whole length of the edge of both jaws, simple, cylindrical, conical, 

 smooth. Dorsal fin falcate, rarely wanting. Pack rounded. Tail 

 compressed, keeled. The pectoi'al fin moderate, ovate, on the upper 

 part of the sides of the chest ; fingers 4 or 5, short, each formed of 

 four or five joints. 8kull beaked ; the maxillary bones simple, ex- 

 panded out or shelving over the orbits. Intormaxillaiy bones 

 moderate, only partly covering the maxilla. The breast-bone elon- 

 gate, formed of three portions, with the first three pairs of ribs on 



