1883.] PROF. FLOWER ON THE DELPHINID^. 477 



Such is at present all the material available for the history of 

 these interesting Dolphins. The various individuals described, some 

 from the Cape of Good Hope, some from New Zealaud, all present 

 strong points of agreement as to size, form, cranial characters, 

 number of vertebra) and of teeth, and general distribution of surface 

 colouring. They obviously form a natural group ; but before we can 

 determine whether to consider them as forming one or more species, 

 we require to know how far the differences hitherto pointed out 

 depend upon errors of observation and imperfect description and 

 delineation, and how far upon individual or sexual variation. It 

 must be noted that hitherto all the Cape specimens recorded have 

 obtusely triangular dorsal fins, while those from New Zealand have 

 had the same ors:an of a rounded outline. If the two forms should 

 prove to be distinct, the name C. heavisidii, Gray, will be retamed for 

 the former, while G. hectori (Van Beneden) will be adopted for the 

 latter, which may or may not include Hector's so-called Electra 

 clancula. If the distinctive cliaracters of the latter should prove to 

 be valid, it will require a new name. 



A form evidently closely allied, as far as cranial characters tell, 

 is that represented by a skull in the British Museum, from the 

 coast of Chili, to which Dr. Gray gave the name of Delphinus 

 eulropiu (P. Z. S. 1S49, p. 1), and subsequently erected into the 

 type of his genus Eutropia, under the designation of Eutropia 

 dicJciei. Although a second, smaller, and younger skull of the same 

 form has since (in 1881) been received by the Museum from the 

 same locality, nothing is as yet known of its external characteristics, 

 or of the remainder of the skeleton. Specific distinction from 

 C. heavisidii may readily be found in greater size (its extreme 

 length being 360 mm.), longer and narrower rostrum, and larger and 

 rather more numerous (30 to 32) teeth. It must be borne in mind, 

 however, in making this comparison, that all the skulls of C. 

 heavisidii hitherto examined seem to belong to immature specimens, 

 and that the original " Eutropia dickiei" of the British Museum 

 is apparently that of a perfectly adult animal. The form of the 

 pterygoid bones (broken in the type specimen, but preserved in the 

 younger one), however, though of the same general type, is appreci- 

 ably different from that of those of C. heavisidii. They are longer 

 from before backwards, and their inner edges, though never in con- 

 tact, are more nearly ])arallel, and thus approach more nearly to the 

 normal type of the Dolphins. The palate of the larger species also is 

 laterally contracted in front of the pterygoid bones in a manner not 

 seen in the smaller one. 



Pending the discovery of further evidence as to the characters of 

 this species, I see no reason to separate it generically from Cepha- 

 lorhynchus, and it should therefore bear the name of C. eutropia. 



Pkoc. Zool. Soc.--1883, No. XXXII. . 32 



