134 DR. J. E. GRAY ON THE MUSTELID. [Jan. 24, 
naked portion of the palms not invaded by hair from the carpal 
region. 
Colour above liver-brown ; the long hairs with lighter tips, and 
appreciably lighter on the belly; sides and under surface of head 
and the throat dirty white.”— Baird, N. A. Mamm. 187. 
Mr. George Barnston, in an interesting paper on the Otters of 
North America, in the ‘Canadian Naturalist’ for June 1863, de- 
scribes a small Otter, that destroys the Beavers’ dams in Canada, 
under the name of Lutra destructor, and figures the skull, lower 
jaw, sole, and hind foot. 
“In the Lutra destructor the bones of the skeleton and cranium 
are less massive: the length of the skull being nearly alike (as with 
two specimens taken for exemplification), there is found in the L. 
destructor a less breadth in the postorbital process of the frontal, and 
the whole of the nasal bones are narrower and weaker. The outer mea- 
surement of the cavity of the brain approaches the oval, being convex 
in all aspects, and it exceeds the half of the total length of the 
skull from the occipital to incisors by nearly one-fourth of an inch: 
whereas the enclosing shell or covering of the brain in L. canadensis 
is almost equally half the length of the whole skull, it is also nearly 
flat on the top, presenting no rounded surface except close to the 
occiput, and there is no more decided narrowing of the cavity an- 
teriorly, so that the general outline approximates less to the oval 
form, and more to the shape of a truncated cone. On the lateral 
view, with the lower jaw taken off, the skull of the L. destructor 
exhibits somewhat an arched appearance, the malars and facial 
bones are narrower, and the zygomatic arch rises to two-fifths of 
the height of the skull in the L. canadensis; on the same lateral 
aspect the plane of the head is straighter, the facial line deeper and 
broader, and the zygomatic arch raised to a parallel line of one-half 
the depth of the skull.” 
The figure of the hind foot of L. destructor, fig. 7, shows “ four 
callosities :”? they are to be seen in all the specimens of L. cana- 
densis in the British Museum; so that they are not specific, but 
show that L. destructor is most probably a Lataz, as that is the only 
genus of Otter that I know having such callosities. 
B. Tail elongate, flattened, with a fin on each side; hind feet 
large, rounded. 
16, PreRonuRA. 
Head large, depressed ; eyes small; ears small, round, very hairy 
inside; muzzle hairy; nostrils with only a slight naked space on 
their upper edge; feet very large; toes 5/5, distinct, very largely 
webbed ; tail elongate, subcylindrical, flattened, with a fin-like ex- 
pansion on each side of the hinder half; hind feet large, rounded ; 
claws long, acute; hinder toes very long, two outer ones largest, 
the others gradually shorter to the inner one. Cutting-teeth 6/6 ; 
upper middle ones larger, equal, conical; the outer ones small, 
conical ; inner elongated ; grinders (not examined). 
