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



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

 these interesting Dolphins. The various iudiviJuals describeJ, some 

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

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

 number of vertebrae 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 organ of a rounded outline. If the two forms should 

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

 the former, while 0. hectori (Van Beiieden) will be adopted for the 

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

 clancula. If the distinctive characters 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. 1849, p. 1), and subsequently erected into the 

 type of his genus Eutropia, under the designation of Eutropia 

 dicldei. 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 immerous (30 to 32) teeth. It must be borne in mind, 

 however, in nuiking tliis comparison, that all the skulls of C. 

 heavisidii hitherto examined seem to belong to immature specimens, 

 and that the original " Eutropia dicJciei" 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 0. heavisidii. They are longer 

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

 tact, are more nearly parallel, 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 snniUer 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. 



Proc. Zool. SOC.--1883, No. XXXII. . 32 



