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 fore- 

 going 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 - 25inch 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, 1 7 teeth on each side, occupy- 

 ing 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 I have be- 

 lieved 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. 



We 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 at- 

 tempted by Dr. Hector, and for which no tangible reason can be as- 

 signed, only confusion will be created. 



The occurrence of hidden teeth in the gums of Ziphius aus trails, 

 Burmeister, of which he gives a careful description in his ex- 

 haustive 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 



