CETACEA. 97 



** Head beaked. Nose of skull longer than the brain-cavity. 

 11. LAGENORHYNCHUS, Gray. 



Head rather convex, gradually sloping into the beak in front. 

 Beak short, tapering in front. Lower jaw rather longest. Body 

 elongate, tapering behind, largest at the pectoral fins. Pectoral 

 fins rather far back, rather elongate and slightly falcate. Dorsal 

 fin high, falcate, rather behind the middle of the back. The back 

 with a low, rounded, fin-like ridge near the tail. Tail-lobes rather 

 narrow, elongate. Skull rather depressed, the hinder ends of the 

 maxillary bones expanded, horizontal, and rather thickened on 

 the edge. The nose is short, broad, flat above and rather nar- 

 rowed in front, and scarcely longer than the length of the brain- 

 cavity. The triangle in front of the blowers is elongate, and 

 reaches beyond the middle of the nose of the skull, and the in- 

 termaxillaries are separated by a deep groove filled with cartilage. 



Lagenorhynchus, Gray, Zool. Erebus fy Terror, 34, 1846. 

 Grampus, pars, Gray, Spic. Zool. 2, 1828. 

 Delphinus, sp., Brightwell, Ann. fy Mag. N. H. 1846. 



This genus is easily known from Delphinus by the lowness of 

 the forehead, the short and depressed form of the beak, the poste- 

 rior position of the dorsal fin, the body being attenuated be- 

 hind ; and by the breadth, and flat, expanded form of the nose 

 of the skull. 



The os hyoides of L. leucopleurus is large and broad. 



t Beak very short j nose of skull only as long as head ; teeth 

 nearly to the notch. 



1. LAGENORHYNCHUS LEUCOPLEURUS. WHITE-SIDED 

 BOTTLE-NOSE. 



Skull : brain-cavity large, high at the top behind the blow- 

 hole ; nose nearly as long as the brain -cavity, gradually and regu- 

 larly tapering on each side ; triangle in front of the blower flat- 

 tened and concave behind, with a slightly-raised, lozenge -shaped 

 space in the front half. 



Above bluish black, beneath white, with a large, oblique, grey 

 or white longitudinal streak on hinder part of each side. Teeth 

 ff, small, acute, curved. 



Delphinus Tursio, Knox, Cat. Prepar. Whale, 29, 1838. 

 Delphinus leucopleurus, Rasch, Mag. Zool. 1843, 369; Nilsson, 

 Skand. Fauna, i. 598. 



