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Show 8 DR. J. VON HAAST ON A NEW ZIPHIOID WHALE. [Jan. 4 Unfortunately the skulls were so badly separated from the body that the occipital portion has been cut off, so as to lay the brain-cavity open ; but as they were brought over with the greater portion of the skin still attached, some hitherto unknown and, as I think, peculiar characteristic features in the dentition of a Ziphioid genus have fortunately been preserved. These three skulls accord in many respects with the genus Mesoplodon of Gervais, of which I will point out only one, viz. that they possess one tooth in each ramus of the lower jaw opposite the posterior edge of the symphysis, and of varying size and shape, either hidden below the gum or rising conspicuously above, according to age and sex. They differ, however, from all known species of the genus by possessing in the upper jaw, starting in a vertical line above the posterior border of the mandibular tooth, a series of small conical teeth slightly incurved, which extends to near the gape of the mouth. I may here at once observe that these teeth are neither rudimentary nor are they confined to young animals, because, as I shall show in the sequel, these three skulls are derived from individuals of different ages, of which one is an aged (male ?) animal, in which the row of teeth is best developed. It is thus evident that this series of teeth is a functional portion of the animal, and is constant and necessary for its proper nourishment, some of them being broken off, others evidently worn down from use. That these small teeth, of which the largest stands scarcely half an inch above the gums, are only rooted in the gums, does not lessen their value as a specific character of some importance. Of the species of Ziphioid Whales inhabiting the New-Zealand seas I have obtained three, namely Berardius arnouxii (3 specimens), Ziphius novce zealandice, and Mesoplodon floweri (Haast, MS.), none of which shows the least sign or rudiments of teeth in the upper jaw. Moreover several others have been secured in N e w Zealand and Australia ; but nowhere can I find that, except the teeth in the lower jaw, they possessed any ; and I have looked carefully over all the different papers on the Ziphioid Whales of the northern hemisphere to which I had access, without finding the slightest mention made of the occurrence of such a peculiar feature hi their dentition. On the contrary, Professor Flower in his excellent paper on the recent Ziphioid Whales (Trans. Zool. Soc. vol. viii. part 3), when enumerating their principal structural characters, begins by stating that they have "no functional teeth in the upper jaw." I believe that this term functional is rather ambiguous and can scarcely be applied to the genus under consideration, as we are totally unacquainted with the food on which it subsists, or the manner in which the same is obtained. It is true, these teeth do not grow from alveolar grooves in the maxillaries, but only from a groove in the gums, and have their roots implanted therein; nevertheless I have no doubt that they are always present and do perform as distinct and important functions as those of Kogia or any of the Dolphins which possess teeth of similar form. |
