DELPHINID^E 271 



Delphinus. 1 Teeth very numerous in both jaws, $ to $, 

 occupying nearly the whole length of the rostrum, small, close-set, 

 conical, pointed, slightly curved. Rostrum elongated, usually about 

 double the length of the cranial portion of the skull. Pterygoids of 

 normal form, meeting in the middle line throughout their length. 

 Palate with deep lateral grooves. Vertebrae 73 to 75. Pectoral fin 

 of moderate size, narrow, pointed, somewhat falcate. Second and 

 third digits well developed ; the rest rudimental. 



The type of the genus is the Common Dolphin of the Mediter- 

 ranean (D. delphis, Fig. 97), also found in the Atlantic, and of 



FIG. 97. The Common Dolphin (Delphinus cUlphis). From Reinhardt. 



which a closely allied if not identical form is met with in the 

 Australian seas (D. forsteri) arid in the North Pacific (D. bairdi). 

 Other species are D. janira, D. major, etc. 



Tursiops. z Rostrum tapering moderately from base to apex ; 

 palate not grooved ; symphysis of mandible short ; other cranial 

 characters as in Delphinus. Teeth f-^ to f -, stout (6 to 7 mm. in 

 antero-posterior diameter). Vertebrae : C 7, D 13, L 17, C 27; total 

 64. Limbs as in Delphinus. Represented by the widely distributed 

 T. tursio ; T. catalania being a second form. Fossil remains of this 

 genus from the Italian Pliocene have been recently described. 



Prodelphinus. 3 Rostrum somewhat variable ; mandibular sym- 

 physis short (less than one -fifth the length of the ramus); other 

 cranial characters as in the preceding genus. Teeth f$ to -$, 

 small, not exceeding 3 mm. in diameter. Vertebrae 73 to 78. 

 Limbs as in Delphinus. Four leading types of this genus are 

 recognised (all of which have numerous synonyms) viz. P. obscurus, 

 P. euphrosyne, P. doris, and P. longirostris. 



Peron's Dolphin (Delphinus leucorhamphus, Pe"ron, or Leuco- 

 rhamphus peroni, Lilljeborg) resembles some forms of Prodelphinus in 

 its cranial characters ; but having no dorsal fin, it has been separated 

 generically by some writers. It is not improbable that Delphinus 

 borealis, Peale, from the North Pacific, in which there is likewise no 

 dorsal fin, may be an allied form. 



Steno.*- Rostrum long, narrow, and compressed, very distinct 

 from the cranium ; mandibular symphysis as long as, or longer than 



1 Linn. Syst. Nat. 12th ed. vol. i. p. 108 (1766). 



2 Gervais, Hist. Nat. des Mammifercs, vol. ii. p. 323 (1855). 



3 Gervais, Osteographie des Cttacds, p. 604 (1880). 



4 Gray, Zoology of Erebus and Terror, p. 43 (1846). 



