1883.] 



PROF, FLOWER ON THE DELPHINIDjE. 



511 



1864, p. 425) tliat it might be a young individual of one of the 

 larger species of the genus Orca. 



The principal dimensions of the two skulls, in millimetres, are — 



Schlegel, and L. 



leucopleurus. 



Lagenorhynchus, Gray, Zool. Erebus & Terror, p. 34 (1846). 



Rostrum scarcely exceeding the length of the cranium, broad at 

 the base and gradually tapering towards the apex, depressed. 

 Pterygoid bones normal, meeting in the middle line. Teeth small, 

 not exceeding 4 millim. in diameter, gg to g^. Vertebrae very nu- 

 merous, 80 to 90. Spinous and transverse processes of the lumbar 

 vertebrae very long and slender ; bodies short. Externally, head 

 with a short but not very distinct beak. 



L. albirostris, Gray. 



L. acutus, Gray = i. eschrichtii, 

 Rasch. Closely allied, if not identical, are L. perspicillatus. Cope, 

 and L. obliquidens. Gill. 



L. electra, Gray. Known from skull only. L. asia. Gray. 



L. clanculus, Gray. Known from skull only. Not Electra clan- 

 cula of Hector. 



Here ])robably may be placed — D. cruciger and B. albigena, 

 Quoy and Gaimard ; D. bivittatus. Lesson and Garnot, and D. 

 fitzroyi, Waterhouse. 



B. Dolphins with distinctly elongated rostrum, or beak, generally 

 marked off from the antenarial adipose elevation by a V-shaped 

 groove. In the skull the rostrum considerably exceeds the 

 cranial portion in length. Atlas and axis firmly united ; all 

 the other cervical vertebrae free. 



a. Pterygoid bones of normal form, meeting in the middle line 

 by the whole of their parallel inner edges. Pectoral fins 

 lanceolate. Second and third digits well developed ; the rest 

 rudimentary. 



a. Palate with deep lateral grooves. 



Delphinus, Linnaeus, Syst. Nat. ed. 12, i. p. 108 (1766), 



restricted. 

 The character of tbe palate separates the true Dolphins from all 

 other members of the family. The rostrum is long and narrow, 

 generally about double the length of the cranial portion of the skull. 



34* 



