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Show 12 DR. J. VON HAAST ON A NEW ZIPHIOID WHALE. [Jan. 4, an aged male, the measurements of the third skull under consideration must lead us to the conclusion that it is that of a young half-grown male. Beginning with the lower jaw, the same form as in the foregoing is observable, the rami expanding considerably as soon as we reach the neighbourhood of the alveolar cavity ; and although the * tooth in the same is only small, and stands only 0*25 inch above the edge of the ramus, that alveolar cavity is much more bulged out and has a different form from the first (or female?) skull described. The apex of the tooth was distinctly visible, and seemed to have already pierced the gums when the animal was alive. The row of teeth in the upper jaw, however, which have the same form as in the skull No. 2, are smaller and somewhat more slender. They begin likewise above the posterior end of the alveolar cavity. There are, as in the preceding skull, 17 teeth on each side, occupying a length of 2*48 inches. They stand more closely together than in the supposed female skull No. 1, thus also agreeing with the second skull in that respect. In volume vi. of the Transactions of the New-Zealand Institute, Dr. Hector describes the lower jaw of a Ziphioid Whale under the title " Notice of a variation in the dentition of Mesoplodon hectori, Gray." It is difficult for me to conceive by what process the tooth in the lower jaw which, in Mesoplodon hectori, stands at the anterior end of the ramus, could have travelled as far backwards as to stand now opposite the posterior edge of the symphysis. Hitherto 1 have believed that the position of the mandibular teeth was constant and a valuable specific character-an opinion which, as far as I am aware, is held by the most eminent cetologists, and which the observations I was able to make on the three skulls under review amply confirms. Moreover I wish to add that a comparison of these three skulls with the skull of Mesoplodon hectori, Gray, in the Canterbury Museum, and which is derived from an aged specimen, shows at a glance the distinct specific characters. W e are only at the beginning of the study of our Ziphioid Whales; and I have no doubt that year by year new material will come to hand ; so that by the lumping of two distinct species into one, as attempted by Dr. Hector, and for which no tangible reason can be assigned, only confusion will be created. The occurrence of hidden teeth in the gums of Ziphius australis, Burmeister, of which he gives a careful description in his exhaustive paper, " Descripcion detallada del Epiodon australe " in the ' Anales del Museo publico de Buenos Ayres,' part v. page 328, is a point of great interest. On first thought, one might assume that that specimen was so young that the teeth had not yet pierced the gums, and that animals belonging to that species when full-grown would be possessed of a row of teeth in each jaw resembling those of Mesoplodon grayi,. However, two (and what I think fatal) objections have to be urged against such a theory. The skull of No. 3 belongs doubtless to a younger specimen than |
