SIR SIDXEY HARMER ON COMMERSOn's DOLPHIN. 627 



32. On Coininerson's Dolphin and other Species o£ Cephalo- 

 rhi/nchus. By Sir Sidney F. Harmer, K.B.E,, Sc.D., 

 F.R.S., F.Z.S., Director of the Natural History Depart- 

 ments of the British Museum *. 



(Plates I-III.t) 



[Received May 17, 1922 ; Read May 23, 1922.] 



The literature of the Cetacea includes numerous specific names 

 which are of little use to science, owing to a want of knowledge 

 of the animals to which they were oi'iginally applied. Many 

 descriptions are based on external features alone, while others 

 depend exclusively on osteological chai-acters. The correlation 

 of these two kinds of description is ditficult and often impossible, 

 and there is probably no group which includes a larger proportion 

 of doubtful species than could be found in a complete list of the 

 names which have been given to Cetacea. 



Under these circumstances I have felt much satisfaction in 

 being able, as I think, to rescue one of these doubtful species 

 from its present position. In 1804, Lacepede (pp. xliv, 317) gave 

 a brief description of a Dolphin which had been observed by 

 Commerson, near Tierra del Fuego and in the Straits of Magellan, 

 during Bougainville's voyage round the world. Commerson's 

 MSS., addressed to Buifon, by whom they were sent to Lacepede, 

 included a diagnosis of this Dolphin : — "Tursio corpore argenteo, 

 extremitatibus nigricantibus." It is furtiier stated that the 

 black colour ajDpears only on the " extremities," and that the 

 back and almost all the surface of the animal shine like a 

 polished surface, white and, so to speak, silvered. These 

 Dolphins, somewhat inferior in size to the Common Porpoise, 

 were observed, during the Southern summer, playing round 

 the vessel, and were described as being among the most 

 beautiful inhabitants of the sea. They were given the name of 

 " Le Jacobite," obviously in allusion to their striking black and 

 white colour. 



Quoy and Gaimard (1824, p. 87) mention a Dolphin, " moitie 

 blanc, moitie noir, a museau peu alonge," which they saw at the 

 Falkland Islands. A specimen was killed, but it sank imme- 

 diately. Lesson (1827, p. 181) states that during the voyage of 

 the ' Coquille ' they only once observed, at the Falkland Islands, 

 the Black-and-white Dolphin of Quoy and Gaimard,, and that every- 

 thing authorised him to think it was the Delphinus commersonii. 



* Puljlislied hy permission of the Trustees of the British Museum. 

 f For explanation of the Plates, see p. 638. 



Proc. Zool. Soc— 1922, No. XLIII. 43 



