RODENTIA. 157 
The fossil bones of an unknown species of Lagomys have been 
discovered in the osseous breccia of Corsica. Cuv. Oss. Foss. 
IV,p. 199. 
After the two genera of Porcupines and Hares, come the Roden- 
tia, united by Linnzus and Pallas, under the name of Cavia ; but to 
which it is impossible to affix any other common and positive cha- 
racter than that of their imperfect clavicles, although the species of 
which they are composed are very analogous to each other, both in 
body and habits. They are all from the western continent. : 
Hyprocuerus, Erxleb. 
Four toes before and three behind, all armed with large nails, and 
united by membranes ; four grinders throughout, of which the pos- 
terior are the longest, and composed of numerous, simple and paral- 
lel laminz; the anterior laminz, forked towards the external edge 
in the upper, and towards the internal one in the lower teeth. Only 
one species is known, the 
Hi. capybara; Cavia capybara, L.; Capybara, Marcg.; Capiy- 
goua, Azzar.3; Cabiai, Buff. XII, xlix. (The Capybara.) Size of 
Siam Pig ; the muzzle very thick ; legs short; hair coarse, and 
of a yellowish brown ; no tail. Inhabits the rivers of Guiana 
and the Amazon, where it lives in troops. The Beaver only 
approaches it in size. 
Cavia, Ilig.—Anaa, Fr. Cuv. 
The Cobayes, or Guinea-Pigs, are miniature representatem of the 
Cabiais ; but their toes are separated, and each of their molars has 
only one simple lamina, and one that is forked on the outside in the 
upper ones, and on the inside in the lower. The species best 
known, 
C. cobaia, Pall.; Mus porcellus, L.; Buff. VII, i, (The Gui- 
nea-Pig) is now very common in Europe and America, where 
it is brought up in houses, because its odour is thought to 
drive away Rats. Like all domesticated animals, it varies in 
colour. There is reason for believing it proceeds from an 
American animal called Aperea, which is of the same size and 
’ form, but with a uniform reddish-grey fur. It is found in the 
» woods of Brazil and Paraguay. 
= * Keropon, Fred. Cuy. 
. The Mocos have rather simpler grinders than the Cobayes, each 
being formed of two triangular prisms.. 
ae 
