20 PROFESSOR FLOWER ON RISSO'S DOLPHIN. 



known to science by that naturalist, or even to keep it as a vernacular appellation for 

 the entire species, and thereby continue to associate his name with it. 



Systematic Position. — In Baron Cuvier's time this species, with a vast number of 

 others now generically separated, was included in the genus Delphinus. Mons. F. Cuvier 

 constituted of a group of short-nosed Dolphins the genus Phoccena, embracing with 

 the species now under consideration the Common Porpoise, the Killer (Orca gladiator), 

 the Round-Headed Dolphin (Globiceplialus melas 1 ), and even the Beluga (Histoire des 

 Cetaces, 1836). 



The genus Globiceplialus 2 was formed by Lesson 3 for a still more restricted group, 

 from which Dr. Gray has separated the present animal and its most immediate allies 

 under the name of Grampus*. 



My first impression, obtained from an inspection of the external appearance of the 

 animal, was that it resembled Globiceplialus melas so nearly as hardly to warrant 

 generic separation. There was the same rounded form of forehead, and the same 

 elongated pointed pectoral fins placed low down on the sides of the thorax. It is true 

 that these were developed in a less exaggerated degree than in Globiceplialus, and the 

 dorsal fin was more anterior in position and more elevated ; but such characters can 

 hardly be considered generic, unless accompanied by other and more important structural 

 differences. The teeth, again, have much the same size and form as those of Globi- 

 ceplialus, and are also confined to the anterior part of the jaws ; and I was not then 

 aware that the absence of maxillary teeth was congenital, but supposed that it was due 

 to their being deciduous, a circumstance frequently observed in Globiceplialus at a late 

 period of life. Consequently in the preliminary notice of the capture of this specimen 5 

 the generic name of Globiceplialus was assigned to it. 



After a closer examination of the characters, especially of the skeleton and teeth, of 

 both forms, I am now inclined to think that they may fairly be treated as distinct 

 although closely allied genera, and subjoin the following comparative table of diagnostic 

 characters : — 



Globicephalus. — Teeth in both jaws, 9 to 12 on each side, confined to the anterior 

 half of the rostrum and corresponding portion of the mandible ; sometimes deciduous 

 in old age. 



Vertebras. C. 7, D. 11, L. 12 to 14, C. 27 to 29, total 58 or 59. 



1 This species was first correctly described and figured by Trail, under the name of Delphinus melas 

 (Nicholson's Journ. xxii. 1809, p. 21). Cuvier, unacquainted with Trail's memoir, described and figured it 

 again in the " Rapport sur divers Cetaces," frequently referred to above, as Delphinus globiceps (Annales du 

 Museum, t. xix. 1812). Lacepede's Catodon svineval (Hist. Nat. des Cetaces, 1804, p. 216) may have been 

 founded on some vague idea of this animal ; but the description is almost altogether inaccurate. 



5 Often spelt Globiocephalus. 3 Compl. de Buffon, i. 1828 {fide Agassiz, Nom. Zool.). 



4 Zoology of ' Erebus ' and ' Terror,' p. 30 (1846). Grampus, Gray, Spic. Zool. 2 (1828), was a heterogeneous 

 group, comprising Grampus griseus, Globiceplialus melas, Delphinus aeutus, D. heavisidii, and D. obscurus. 



> P. Z. S. 1S70, p. 128. 



