46 MR. E. T. BENNETT ON THE CHINCHILLIDA. 
ternal, of Lagotis, comparing it as I proceed with the Chinchilla, and occasionally with 
Lagostomus also. My materials for the description of Lagotis are derived from the ob- 
servation of the living animal ; its anatomical examination after death ; and the study 
of its preserved skin and skeleton, which now form part of the Society’s Museum. Of 
Chinchilla the Society has exhibited, during the last five years, no fewer than four living 
individuals ; two of which have lately died, and have thus afforded me the opportu- 
nity of again investigating their internal structure, which I had previously observed in 
the specimen, also from the Society’s Menagerie, formerly dissected by Mr. Yarrell. 
Besides these I have seen two entire skins in the most perfect condition. My know- 
ledge of Lagostomus is founded on a detailed comparison of Mr. Brookes’s account. of 
the skeleton of that animal with the original while in his possession, an examination 
which enables me to bear the fullest testimony to the accuracy of the statements con- 
tained in his paper on the subject. I shall begin with the outward form, the peculia- 
rities of the fur, and its colouring. 
The Lagotis Cuvieri, or long-eared Viscacha, has the size and much of the general 
form of the Rabbit. Its head is of moderate size, broad at the zygomata and narrowing 
towards the muzzle, but considerably thickened out by the pads for implanting the very 
numerous, closely set, and heavy whiskers. These are entirely of a jet black, and ten 
or twelve of them on each side are exceedingly strong, rigid, and of great length, the 
longest when turned backwards projecting more than an inch beyond the tips of the 
ears, and measuring upwards of seven inches in length: they give a striking character 
to the physiognomy of the animal. There is no naked muzzle, the whole circumference 
of the nostrils, with the exception of their margins and an intervening slit, being covered 
with short projecting hairs. The nostrils are simple and oblique; that is to say, di- 
rected downwards and mesiad, so as to approach each other very nearly at their lower 
extremities. In the upper lip the fissure is so deep as to correspond by its sinus to 
the insertion of the incisor teeth. The eyes are not large, but full and prominent, and 
their anterior canthus is nearly equidistant from the base of the ears and the extremity 
of the muzzle. The ears have nearly the form of a long parallelogram regularly rounded 
at the upper end, and equal in length the distance between their base and the muzzle. 
Their breadth is about one third of their length, the respective measurements being one 
inch and three inches. Their anterior margin is rolled round upon itself, sloping in- 
wards from above downwards, and occupying at the lower end more than one third of 
the breadth of the base of the ear. A corresponding fold, extending at the base ta 
about the same distance inwards, commences a little lower down on the hinder margin. 
Behind this there is a supplementary auricle accompanying it for two thirds of its 
length. On the outside the ears are sparingly furnished with short scattered hairs, and 
on the inside still more sparingly, and with hairs still shorter: those which fringe the 
margin are rather longer, particularly on the anterior edge, where they are also more 
copious. 
The neck is short and thick, and the body somewhat heavy in its proportions ; or at 
