OCR Text |
Show 1883.] PROF. FLOWER ON THE DELPHINID,£. 505 vertebras distinct, or with irregular unions towards the middle of series. Manus small, short and broad ; second and third digits nearly equal, fourth slightly shorter. No dorsal fiu. One species, M. monoceros, Linn. Arctic seas. DELPHINAPTERUS, Lacepede, Hist. Nat. des Cetaces, Tabl. des Ordres &c. p. xii (1804) K Beluga, Gray, Spicilegia Zoologica, p. 2 (1828). Agrees with the last in all the characters above mentioned except the dentition. Teeth g to y0> of moderate size, occupying the anterior three-fourths of the rostrum only and corresponding portion of the mandible, separated by intervals considerably wider than their own diameter, and implanted obliquely, the crowns inclining forwards, especially in the upper jaw. D. leucas (Pallas), the Beluga or White Whale of the Arctic seas, is the only well-established species. It has been divided into several (rhinodon, declivis, and angustatus) by Cope, but these require confirmation. A skull of a young animal in the British Museum, not distinguishable from the northern form, but said to be from the coast of New Holland, was described in 1827 by Dr. Gray, under the name of D. kingii. N o further light has since been thrown upon this habitat. b. Atlas and axis firmly united. P H O C A N A , Cuvier, Regne Animal, i. p. 279 (1817). a. Crowns of teeth laterally compressed. Teeth ^|, small, occupying nearly the whole length of the rostrum, with compressed spade-shaped crowns, separated from the root by a constricted neck. Rostrum of skull rather shorter than the cranium proper, broad at the base and tapering towards the apex. Premaxillae raised into tuberosities in front of the nares. The frontal bones forming a somewhat square elevated protuberance in the middle line of the skull behind the nares, rising altogether above the flattened nasals (see fig. 2, p. 471). Pterygoids very small and widely separated in the middle line. Symphysis of mandible very short. Vertebrae : C. 7, D. 13, L. 14, C. 30 ; total 64. First to sixth cervical vertebrae, and sometimes the seventh also, coalesced. Manus of moderate size, oval, slightly falcate ; second and third digits nearly equal in length, fourth and "fifth well developed but shorter. Dorsal fin near the middle of the back, triangular ; its height considerably less than the length of the base ; its anterior edge frequently furnished with one or more rows of conical horny tubercles. Phocana communis, F. Cuvier. Hab. European and American coasts of North Atlantic. A closely similar if not identical species 1 The Beluga being the first mentioned and type of this genus, in fact the only species of those now recognized by cetologists known to Lacepede, should remain as its representative, although by Gray and others it has been removed to a new genus, and the name Belphinapterus transferred to species unknown to its founder. |