330 MAMMALIA: CETE. LI. 



FAMILY CXCI. DELPHINID^. (THE DOLPHINS.) 



Cetaceans with well developed teeth in both jaws (deciduous in 

 the upper jaw in one genus) and a single, somewhat complicated 

 nasal tube. Genera 17, species about 40, including the smaller 

 of the Cetacea, but many of the most active and voracious of the 

 species. 



a. Head with an elongate beak; a distinct dorsal fin. 

 b. Teeth in each jaw about 44; truncate at tip; palate without lateral 



grooves TURSIOPS, 567. 



bb. Teeth in each jaw 80 to 120. 



x. Palate without lateral grooves PRODELPHINUS, 567 (b). 



xx. Palate with deep lateral grooves DELPHINUS, 568. 



aa. Head with a very short beak or none. 

 c. Teeth in both jaws persistent. 



d. Teeth flattened; dorsal present PHOCJSNA, 569. 



dd. Teeth terete. 



e. Dorsal fin well developed. 

 f. Teeth in each jaw 44 to 46; dorsal fin falcate. 



LAGEKORHYKCHUS, 570. 

 ff. Teeth in each jaw 16 to 24. 



g. Dorsal moderate ; head almost globular; P. long and narrow; 

 teeth rather weak, none in corner of mouth. 



GLOBICEPHALUS, 571. 



g(]. Dorsal very high, sword-shaped, its height greater than length 

 of pectorals; teeth very strong; skull massive. ORCA, 572. 

 ee. Dorsal fin obsolete ; pectoral short; teeth few. 



DELPHINAPTERUS, 573. 



cc. Teeth in upper jaw feeble, disappearing with age ; 6 to 14 bluntish 

 teeth in lower jaw ; dorsal fin low, rather posterior. GRAMPUS, 574. 



567. TURSIOPS Gervais. (Lat., tursio, porpoise.) 



1087. T. tursio (L.). BOTTLE-NOSE DOLPHIN. Gray above, 

 pure white below; beak short and stout; teeth ^f. Vertebrae 

 7_[_18-J-37. L. 11 feet. N. AtL, common; caught in numbers 

 at Cape May. (Eu.) 



1088. T. erebennus (Cope.) BLACK DOLPHIN. Wholly black ; 

 premaxillaries forming an elevated, rounded ridge ; teeth |~|. 

 Vertebras 7-J-ll-f-16-|-?. L. 8 feet. Atlantic Coast of U. 8. 

 (tpffcwfa, black as Erebus.) 



567 (b). PRODELPHINUS Gervais. 



1089. P. plagiodon (Cope) SPOTTED DOLPHIN. Form of 

 D. delphis ; dorsal high, recurved ; P. broad ; beak stout. Dark 

 purplish slate-color, above ; white below ; back and fins spotted 

 with pale ; lower parts spotted with dark slate. L. 10 feet. N. AtL, 

 S. to N. J. (nXdyios, oblique ; o8o>i>, tooth.) 



