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Show 476 PROF. FLOWER ON THE DELPHINID^E. [Nov. 20, is peculiar in the deep indentation between the lobes of the caudal fin, and especially in the dorsal fin being rounded in outline, unlike that of any "other known Cetacean, but rather resembling the adipose fin of a Salmon on a large scale. Hutton simply describes the dorsal fin as " truncated." Both Hector and Hutton describe the distribution of the white markings on the black surface as in D. heavisidii, but with this striking difference, that in the New-Zealand animal the " nose and forehead is pure white," bounded by a crescent of black behind the blowholes. The teeth also appear to be more numerous, being usually 31 and sometimes 32 on each side of each jaw. A statement made by Dr. Hector that " the cervical vertebrae are ankylosed into a solid mass, 1*3 inch in length," is also very important, but requires elucidation and confirmation. An important contribution to our knowledge of the animals of this group has been lately made by the publication by Van Beneden (Bull, de l'Acad. Roy. de Belgique, 3me ser. t. i. no. 6, juin 1881) of a description and figure of the external characters, with osteological details, of a " Nouveau Dauphin de la Nouvelle-Zelande," which, misled by Hector's identification of the common Cephalorhynchus of tbe seas around that land with Gray's Electra clancula, he has named Electra hectori. But the description of the skull, the form of the pterygoid bones (a drawing of which Prof. Van Beneden has most obligingly sent me), and especially the number of the vertebrae, show that it is widely removed from the Lagenorhynchi, and must enter into the group of Cephalorhynchi. In fact Van Beneden says that " la tete est parfaitement conforme a celle qui est representee sous le nom de Cephalorhynchus heavisidii (* Osteographie,' Atlas, pl. xxxvi. fig. 1)." He further states:-" Si nous comparons le dessin du crane et du corps avec les figures publiees par M . James Hector sous le nom de Electra clancula, nous trouvons une similitude presque complete avec cette espece: le crane offre exactement la meme conformation et les dents se correspondent par le nombre comme par la forme." The dorsal fin has almost exactly the same rounded form, though with less elevation, and the caudal fin the same deep indentation between the widely divaricated lateral lobes. The coloration appears only to differ in the upper and anterior part of the head and beak being black instead of white, as in Hector's specimens. In this we have a return to the original figures of D. heavisidii and D. hastatus. From Rapp's figure of the latter, however, Van Beneden's differs in the under surface of the chin and throat being white instead of black. The teeth are |-_, the largest being 2 millim. in diameter. The vertebrae are C. 7, D. 14, L. 15, C. 27; total 63. The atlas and axis are united, the remainder of the cervical vertebrae free. The manus is narrow, the first and fifth digits being quite rudimentary. The following are the numbers of the elements of each digit, including metacarpals:-I. 1., II. 6, III. 4, IV. 3, V. 1; the individual described was, however, very young, being only 3 feet 6 inches in length, and therefore all the phalanges may not have been ossified. |
