96 Transactions.—Zoology. 
Mesoplodon layardi (or, as I should call it, Dolichodon layardi) has a much 
longer and more attenuated lower jaw, and much more slender teeth than 
the Chatham Island specimen figured and described by Dr. Hector under 
that name ; and I have very little doubt in my own mind that the Chatham 
Island specimen will be found, when more perfect specimens are obtained, to 
be the representative of a very distinct species of Dolichodon, which I would 
propose provisionally to designate as Dolichodon traversii—a curious comment 
on the comparative anatomists, who think that Dolichodon layardi of the Cape, 
Callidon güntheri of New South Wales, Petrorhynchus capensis of the Cape, 
etc., etc., “all differ in so trifling a degree as not to exceed the range of 
individual variations one often meets with in comparing a series of skulls of 
the same species." Surely the author means domestic animals, and entirely 
leaves out of the question the experience gained by the study of wild ones, and 
the evidence afforded by the study of their geographical distribution. I must 
think that when these authors become more experienced they will wish their 
observations to have a “tacit burial and oblivion,” and perhaps, themselves 
learn how to define genera and species. 
15. Berardius hectori. 
I know nothing of this skull but from the figures and description of Dr. 
Hector, and the skull has never been in England, so that I do not think 
that any comparative anatomist has had the opportunity of seeing it. Dr. 
Hector considered it the young of B. arnouxi. I at once saw that it was 
different, but as it has the teeth in the front of the jaw, like Berardius, I 
considered it best (and am still of the same opinion) to retain it in that genus, 
with which it agrees in the position of its teeth as developed in the adult 
animal, and in geographical distribution; and your tracings of the ear-bones of 
the two species show that there is a great affinity between them in the very 
peculiar manner in which they are dotted. I consider the position of the teeth 
a more important zoological character than a slight difference in the 
“conformation of the naso-premaxillary region,” a part that, as every zoologist 
who has examined several skulls of different ages in the same species of Cetacea 
knows, is very apt to vary; but when a comparative anatomist draws his 
conclusions from figures on the examination of a single specimen of a group, 
he is often liable to be misled as to the value of the characters to which he 
attaches much importance. Nothing showed this better than the published 
results of the labours of a comparative anatomist, who has named, but not 
defined, a multitude of species and genera from fragments of fossil bones, but 
who, when he attempted to name recent skulls, as of crocodiles, of which he 
has perfect specimens under his eyes, named and described and published what 
we now regard as three distinct species in one case, and two distinct species 
in another, under the same name ; and, on the other hand, a series of skulls of 
