CETACEA. 103 



8. LAGENORHYNCHUS THICOLEA. 



Skull rather narrow behind. Beak elongate, about ^ longer 

 than the length of the head, rather dilated and concave above 

 behind, with the side edges in front of the notch elongate, keeled 

 and turned up ; the middle of the beak flat, with flat shelving 

 sides, the shelving part being broader and forming a slight keel 

 in front. Intermaxillaries flat, gradually tapering. Triangle to 

 near middle of the beak, concave on the sides and keeled in the 

 middle behind. Teeth f ? very slender, curved, elongate, conical, 

 tapering, acute ; the front one very small. 



Lagenorhynchus Thicolea, Gray, Proc. Zool. Soc. 1849; Zoo/. 



Erebus $ Terror, t. 36, ined. Skull. 

 Inhab. West coast N. America. 



a. Skull. Imperfect behind. From Dr. Dickie's Collection. 



in. lin. 



Length of skull, entire 14 6? (end of nose injured.) 



beak 8 4 



teeth-line 7 



lower jaw 12 3 (entire.) 



Width at orbits 7 



notch 3 11 



middle of beak 2 2 



intermaxillary at middle 1 2 



of condyles 3 



12. DELPHINAPTERUS. 



Head rather convex, shelving towards the nose. Nose rather 

 produced, obscurely divided from the forehead. Dorsal fin none. 

 Back rounded. Pectoral oblong, rather slender. Skull mode- 

 rate ; beak broad, depressed, tapering, rounded above ; the tri- 

 angle before the blower, elongate, extending nearly to the middle 

 of the beak. Palate flat. Teeth conical, tapering, acute, curved. 

 Symphysis of the lower jaw short. 



Delphinapterus, Gray, Zool. Ereb. fy Terror, 35. 



Tursio, pars, Wagler, N. S. Amph. 34. 



Delphinus, sp. Lacep. 



Delphinapterus, sp. Blainville, not Lacep. ; Lesson, Voy. 



1. DELPHINAPTERUS PERONII. PERON'S DOLPHIN. 



Black ; beak, pectoral fins, and under part of body white. 

 Teeth If-fS. 



Delphinus Peronii, Lacep. Cet. 517; F. Cuv. Cetac. 164; D'Orb. 

 Voy. Amer. Merid. Mamm. t. 21. f. 5. 



