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Show 496 PROF. FLOWER ON THE DELPHINID^. [NoV. 20, complete comparison, absolute certainty on this point cannot be attained. But as the species seems to be a common one both at the Cape of Good Hope aud New Zealand, the question will probably soon be settled by the examination of recent specimens. A skull is also figured in Gervais's ' Osteographie ' under the name of Lagenorhynchus breviceps (pl. xxxvi. fig. 2). There is a skeleton at Leiden from the Cape, described by Schlegel in his ' Abhandlun-gen ' (p. 22). The figure of the upper surface of the skull (tab. 1. fig. 3) is not quite correct, the rostrum not being sufficiently rounded at the sides. The vertebrae are C. 7, D. 13 (15?), L, 20 (18 ?), C. 33, total 73. The teeth about ~Q. In the British Museum are four skulls, two from the Cape and two without locality. In the College of Surgeons Museum two, both from New Zealand ; and there is one skull in the Cambridge University Museum. Hector figures a skull from N e w Zealand (Trans. N.-Z. Inst. vol. v. pl. i.). The teeth in all these specimens are from 30 to 33 in number. Those in the Cambridge specimen are slightly larger than in the others, being almost 3 millim. in diameter. In all the "triangle in front of the blowers," formed by the premaxillae, is flat and elevated on each side above the maxillae, which slope down laterally to the supraorbital ridge. The most opposite form to this among the Dolphins is Steno, where tbe " triangle " is concave, the middle part being sunk between the lateral ridges, and though the latter are raised above the supraorbital plates of the maxillae, these, instead of falling away laterally, rise up, forming an elevated supraorbital ridge. Most of the other Dolphins are intermediate in this respect. In the rostrum the premaxillae are thick and well raised above the maxillae, as in Tursiops tursio, to which the cranium bears considerable resemblance, though of much smaller size. Clymenia similis, Gray, from the Cape of Good Hope, is probably of the same species ; the only difference being a constriction of the posterior part of the palate in the region of the palatine bones, as figured by Gray (P. Z. S. 1868, p. 147) ; but this is a character which varies in different specimens of C. obscura. A single skull in the British Museum (from the Pacific Ocean) described and catalogued as Lagenorhynchus thicolea1, and subsequently as Electra thicolea, and figured under the former name in the supplementary plates to the ' Zoology of the Erebus and Terror' (pl. 36), is very like that of Clymenia obscura ; but without knowledge of the rest of the skeleton, it is impossible to say whether it really belongs to this group or to the one to which Dr. Gray assigned it. It is of the same size as C. obscura, but the rostrum is more depressed, the premaxillaa less prominent, and the nares and the premaxillae in front of the nares are narrower. The lower jaw is somewhat stouter, the ramus deeper from above downwards, and the symphysis more vertical. The most valid distinction, however, seems to be in the teeth, which are more numerous and rather more slender and close together. Unfortunately they are very incomplete in this much mutilated 1 P. Z. S. 1849, p. 2. |