162 . Mr. Tuompson’s Description of 
toes or thumbs extremely short and small, the whole armed with 
sharp claws, those on the exterior and interior toes being small 
in proportion: tail about six inches in length, scaly, with a few 
scattered setose hairs: testicles in the male very large, and situ- 
ated under the base of the tail. The two upper teeth (vide Fig. 9.) 
are placed without the rictus or opening of the mouth, which is 
not larger than to permit a grain of Indian corn to pass through 
it. The cheek pouches are formed by a duplicature of the 
common integuments, open below, extending from the base of 
the upper teeth to the throat, and as high as the eye and ear: 
these cavities are lined throughout with scattered whitish hairs, 
and formed in the same manner as the abdominal pouch of Di- 
delphis, &c., not at all in the way described by Buffon of the 
Hamster (Mus Cricetus) and the other pouched rats hitherto 
discovered. The body is covered with fine lanceolate spines, 
declining towards the throat and belly into a coarse setose 
hair, and every where intermixed with a finer kind of hair. 
The whole of the upper parts are of a purplish-brown colour; 
lower part of the cheeks, throat, inside of the limbs, belly, 
and under half of the tail, white ; upper half of the tail nearly 
black. : 
The habits of this tribe of rats are singular and curious : 
where numerous, they do incalculable mischief in barns and 
granaries; for, not satisfied with what they can eat on the spot, 
they stow away and carry off in their check pouches no inconsi- 
derable quantity, to be deposited in their retreats for times 
when food is not to be procured from without. 
The present species, in addition to being covered with spines, 
differs from the rest included in the same section, in the great 
' length of the tail. Some doubts might be entertained whether 
it did not more properly belong to the genus Hystrix ; but in- 
i deed, 
