OCR Text |
Show 1883.] PROF. FLOWER ON THE DliLPHINlD.E. 491 identical, or at all events an allied species, its external characters being evidently those of a Lagenorhynchus ; but without any knowledge of the form of the cranium, this is a point which cannot be determined. The New-Zealand species described by Hector under the name of Electra clancula, is, as stated above, a Cephalorhynchus, as is also the Electra hectori of Van Beneden, and they have therefore nothing to do with the present group. Two species of this genus are so frequent in the North Atlantic, especially off the British and Scandinavian coasts, that the number of skeletons in museums is sufficient to determine their osteological characters quite satisfactorily, although there are considerable discrepancies in the accounts of the external appearance and coloration of the specimens which have fallen under the notice of naturalists. L. albirostris (Gray, Ann. & Mag. N. H . 1846) has fortunately had only one specific name bestowed upon it. Variations in the form and colour, depending partly on age, are shown in the descriptions and figures of two British specimens, both young, by D. J. Cunningham and J. W . Clark, in P. Z. S. 1876. In the first, captured off Great Grimsby, the vertebral formula is C. 7, D. 15, L. & C. 68, total 90. In Clark's specimen, from Lowestoft, there are C. 7, D. 14, L. 24, C. 46 = 91, the last being composed only of cartilage. The two first cervical vertebrae appear always to be united, the rest being free. In a skeleton in the Museum of the College of Surgeons from Norway the vertebrae are C. 7, D. 14, L. & C. 67, making a total of 88 ; possibly one or two small terminal caudal vertebrae may be missing. Of the second British species the synonymy is involved in some difficulty. Schlegel, in his ' Abhandlungen aus dem Gebiete der Zoologie und vergleichenden Anatomie,' Heft 1, Leiden, 1841, p. 23, described from the skeleton alone, received from the Faroe Islands, a species of Dolphin which he considered new to science, under the name of Delphinus eschrichtii. He says that of the external form nothing is known ; but the description of the skeleton, with a figure of the skull, and the fact that the skeleton is still to be seen in the Leiden Museum, are sufficient to identify the species intended. At the conclusion of his description he adds:--" Vielleicht gehdrt der von Gray, Spic. Zool. i. p. 2, mit ein Paar Worten, unter dem Namen D. acutus, beschriebene Delphinschadel hierher, welche Annahme besonders durch die gegebenen Masse Wahrscheinlichkeit erha.lt. Mit Gewissheit aber liisst sich ohne eine genaue Beschreibung und Abbildung dieses Schiidels nichts bestimmen." In 1843, Rasch described and figured (in a small folio pamphlet published at Christiania) the external and principal osteological characters of a Dolphin, of which a herd of twenty-three were taken in the Bay of Christiania in June of the previous year, under the name of Delphinus leucopleurus. There is no doubt but that these were identical with the Leiden skeleton named two years before bv Schlegel D. eschrichtii: therefore leucopleurus, otherwise a very appropriate name, is not admissible. The question remains between Gray's acutus and Schlegel's eschrichtii. The description and figure in the ' Spicilegia ' of the skull contained in Brookes's |