90 
MAMMALIA. 
Whale, Mr. Brown states that “ the whiskers consist of nine or 
ten short rows of bristles, the longest bristles anteriorly. There 
are also a few bristles on the apices of both jaws, and a few hairs 
stretching all along the side of the head for a few feet backwards. 
On the tip of the nose are two or three rows of very short white 
hairs, with fewer hairs in the anterior rows, more in the posterior. 
I have reason to believe that some of these hairs are deciduous, as 
they are often wanting in old individuals.” Notwithstanding 
their abnormability of external form, and of their mode of life, 
as compared with the generality of the class Mammalia, it is thus 
seen that even the great toothless Whales tend to exhibit one of 
the usual characteristics of the class to which they appertain, j 
which is to be clad with hair or fur ; and it is highly probable I 
that it has been overlooked in sundry species of them. 
Of the three subfamilies of Balcenopievidoe , the Meg apt evince j 
comprise three genera — Megaptera , Poescopia , and Eschvichtius ; 1 
the Physalince comprise Benedenia, Physalus , Cuvierius, and Sib- 
baldius ; and the Balcenopt evince consist of one genus only — 
Balcenoptevus. 
Many naturalists are of opinion that Dr. Gray carries the dis- 
crimination of these genera to excess ; but, after briefly assigning 
certain distinctions, it is remarked by him that “ the student 
must not run away with the idea that because the characters of 
the genera here given are taken from a few parts of the skeleton, 
they are the only differences that exist between the skeletons of 
the different genera and species. The form of the head, and the 
peculiarities of the cervical vertebrae, of the ribs and of the blade- 
bone, have been selected, after a long and careful comparison 
of the skeletons, as the parts which afford the most striking 
characters that can be the most easily conveyed to the mind of 
the student in a few words, and therefore best adapted for the dis- 
tinction of the genera and species.” It is at least tolerably certain 
now that the species of these huge marine creatures are sur- ; 
prisingly numerous, instead of their being comparatively very few, ! 
as was supposed formerly ; and several of them have only recently 
become adequately recognised, whilst by far the greater number 
are still insufficiently known to be regarded as definitely estab- 
lished. Here we can do little more than briefly indicate the 
principal forms. 
