Hzcron.— Votes on the Whales of the New Zealaad Seas. 841 
Similar teeth in the gum of the upper jaw have, however, been 
previously recorded for the closely-allied Ziphius cavirostris; but, as 
Professor Turner remarks in describing a skull of this species found 
in Shetland, “ such teeth are quite rudimentary and functionless, and 
the presence or absence of such aborted organs ought no more to form the 
basis for establishing a specific difference, than should the entire absence 
of teeth both in the upper and lower jaw of the Shetland cranium be a 
reason for regarding it as a distinct species."* 
10. MzsoPLODON LAYARDI. 
Dolichodon layardi, Gray; Cat. S. and W., 353; Hector, Tr. N.Z. Inst., V., 166. 
Dolichodon traversi, Gray ; Trans. N.Z. Inst., V., 96. 
Mesoplodon layardi, Flower; Nature, VIL., 368. 
Mesoplodon floweri, v. Haast ; Trans. N.Z. Inst., IX., 442. 
Only five or six examples of this curious and generally supposed 
abnormal form of ziphioid have yet been met with, and of these I have seen 
four, (1) a lower jaw from the Cape of Good Hope, collected by the Chal- 
lenger Expedition, (2) a lower jaw I have already described from the 
Chatham Islands,t (8) the complete skeleton in the Canterbury Museum, a 
very complete anatomical description of which has been given by Dr. von 
Haast,} and (4) the skeleton in the Sydney Museum, which has been made 
the type of a new species, Mesoplodon güntheri, Krefft, but which Professor 
Flower considers to belong to the species now under review.§ 
In the last specimen the teeth are not so fully developed into the wonderful 
strap-shaped arches as in the type, but they are evidently intermediate in 
their form between it and the triangular tooth of M. sowerbyi. This skeleton 
has not been yet described, I believe, but Mr. Scott states| that he has 
compared it with the drawings of the skeleton of M. sowerbyi given by Van 
Beneden and Gervais, and cannot detect any essential difference of structure 
between them. The other species I have seen, although each has received 
a different specific name, are only distinguished by a slight divergence in 
the form of the mandible, and the manner in which the large abnormal 
tooth or rather tusk has been bent or worn, which characters are obviously 
due to individual variation. 
The skeleton described by Dr. von Haast is of a mature and probably 
an aged animal, and as the other specimens that have large tusks corres- 
pond in size, and the osteology in most points agrees with other Mesoplo- 
donts, it is not improbable that it may be only the aged condition of some 
species already known from immature individuals. Dr. von Haast states 
* Trans. Roy. Soc. Edin., XXVI., 769. 
+ Trans. N.Z. Institute, V., 166. 1 Trans. N.Z. Inst., IX., Art. LV. 
$ Nature, VIL, 368. || Mamm. Recent and Extinct, p. 116. 
