232 DELPHINID^. 



the La Plata, of which the following is a description, is prohably the 

 same as Stenodelphis Blainvillei ; it is figured Voy. Amer. Merid. 

 t. 23. The skull of this animal was not examined nor preserved. 

 It was blackish, pale beneath, with a white streak along each side 

 from behind the blower, where it is broadest and gradually becoming 

 narrower behind, not quite reaching to the tail. 



According to Desmarest, FreminviUe saw a dolphin on the coast 

 of Brazil which was 15 feet long, with a very convex forehead ; 

 ashy, with a white streak on each side of the head, on the back, 

 throat, and belly. 



2. STENO. 



Head convex. Forehead convex. Beak moderate, tapering. Body 

 elongate, fusiform. Pectoral fin moderate, ovate, falcate. Dorsal 

 falcate, in the middle of the back. Skull round, subglobular. Fore- 

 head erect. Beak elongate, compressed, higher than broad, tapering 

 in front, convex above. Triangle elongate, deep, produced rather 

 beyond the teeth-line. Palate convex, not grooved on the side. 

 Lower jaw elongate, compressed in front ; symphysis elongate, about 

 one-fourth the length. 



Steno, Gray, Zool. JErebus ^ Terror, 43, 1847 ; Cat. Cetac. B. M. 1850, 

 127; Proo. Zool Soc. 1864, 236. 



This genus is at once known from Lagenorhynchus and Debphinus 

 by the length, compression, and tapering |brm of the beak of the 

 skull. 



The foetus of Steno fuseus is very peculiar for the elongated taper- 

 ing head ; the pectoral fins are rather large, strongly falcate ; the 

 dorsal rather beyond the middle of the back. Its tongue is flat on 

 the top, and nearly as broad as the space between the sides of the 

 jaws ; it is entire on the edges of the sides, and slightly dilated in 

 front, crenulated on the edge, and with a larger flat lobe in the 

 middle of the tip. (See ' Zool. Erebus and Terror,' t. 26. f. 1, a, b, c.) 



a. Beak separated from the forehead hy a cross groove^ 



b. Beak scarcely separated from the forehead. 



a. Beak separated from the forehead hy a cross groove, 



1. Steno Malayanus. The Malay Dolphin.. 

 Grey-ash above and below. Nose of skuU about three-fifths of the 

 entire length. Teeth f|. 



Delphinus Malayanus, Lesson, Voy. Coq. t. 9, f. 5 ; Hist, CStae. 152 ; 



SchUgel, Abh. 1. t. 1, 2. f. 2, t. 4. f. 3 (skull and teeth). 

 D. Capensis, Bapp, Cetac, t. 2. f. 1 (not Cfray nor Cuv.). 

 D. Bappii, Beichb. Cetac. iii. 48. 1. 18. f. 5, 7. 

 J), plumbeus, Cuv. B. A. i. 288 ; F. Om. Citac. 151 ; Mamm. lAthog, 



t ; Pucheran, Bev. ^ Mag. Zool. 1856, 146. 

 Steno Malayanus, Gray, Zool. Ereh. 8; Terror,^ ; Cat, Cetac. B, M, 127. 



Inhab. Indian Ocean. 



