496 CUVIER'S ‘CHINCHILLA. |) CHAP. 
to a separate family which will include but the one species, 
D. branickit. 
Fam. 6. Chinchiliidae.—This family, likewise South American; 
contains three genera,’ all of which agree in having long limbs, 
especially the hind-limbs, and a bushy and. well-developed tail. 
The hair is exceedingly soft, hence the commercial value of 
“ ghinchilla.” 
The genus Chinchilla, containing but a single species, C. lani- 
ger, is a small and squirrel-like creature, living at considerable 
heights in the Andes. The eyes, as it is a nocturnal creature, 
are naturally large; and so also are the ears. The fore-feet have 
five toes, the hind-feet only four; they are furnished with feeble 
nails. The innermost toe of the hind-foot has a flat and nail-like 
claw. There are thirteen dorsal vertebrae, and the long tail has 
more than twenty. The clavicle is well developed, as in the 
other genera of this family. The large intestine of this animal 
is extraordinarily long; the proportions of the different regions 
of the gut are shown by the following measurements: small 
intestine, 820 mm.; caecum, 125 mm.; large intestine, 1340 
mm. Such a disproportion between the large intestine and the 
small, to the advantage of the former, is a very strange fact in 
the anatomy of this Rodent. 
The genus Lagidiuvm (also called Lagotis), which includes 
“ Cuvier’s Chinchilla,’ is also a mountain dweller. There are 
several species of this genus, which differs from Chinchilla 
by the complete abortion of the thumb and of the great toe. 
The intestinal proportions are those of Chinchilla. The ears and 
tail are long. LZ. cwviert measures 14 feet in length. 
Lagostomus, again, has but one species, L. trichodactylus. The 
animal has a tail about half the length of the body. The digits 
are reduced as compared with Chinchilla, there being but four on 
the fore- and three on the hind-feet. There are only twelve dorsal 
vertebrae, and seven ribs reach the sternum. . In the skull a dis- 
tinguishing mark from the last two genera is the separation of 
the infra-orbital foramen into two by a thin lamella of bone. The 
large intestine is between one-half and one-third the length 
of the small intestine, and thus differs much from that of 
Chinchilla, 
1 An account of the three genera is to be found in Zrans. Zool. Soc. 1. 1833, 
p- 35, by Mr. E. T. Bennett. 
