134 MAMMALIA. 
and stones, the strength of which is annually increased, and which 
finally, by the progress of vegetation, becomes converted into a hedge. 
Each hut serves for two or three families, and consists of two stories ; 
the upper is dry for the residence of the animals, and the lower un- 
der water for their stores of bark, &c. The latter alone is open, 
and the entrance is under water, having no communication with the 
land. The huts are a kind of rude wicker-work, being made of in- 
terwoven branches and twigs of trees plastered with mud. There 
are always several burrows along the bank, in which they seek for 
shelter when their huts are attacked. They only reside in these 
habitations during the winter; in the summer they separate, and 
live solitarily. The beaver may be easily tamed, and accustomed to 
feed on flesh. It is of a uniform reddish-brown colour, andthe fur, 
as is well known, is in great demand for hatters. It is sometimes 
found flaxen coloured, at others black, or even white. 
Notwithstanding we have carefully compared the beavers which 
burrow along the banks of the Rhone, the Danube, the Weser, and 
other rivers, with those of North America, we are unable to deter- 
mine whether the former are distinct species, or are prevented from 
building by the vicinity of man. 
Myoporamus, Commer. 
The Couias resemble the Beaver in size, in their four molars being 
compressed nearly alike, in their powerful yellow-tinted incisors, and in 
their five-toed feet, the hinder ones of which are palmated; but their tail 
is round and elongated. They are aquatic animals also. One only is 
known, the : 
M. coipus; Mus coipus, Molin., Geoff. Ann. Mus. VI. pl. xxxv. 
(The Couia.) Which lives in burrows along the banks of rivers 
throughout a great part of South America. The fur, which is 
of a yellowish grey, mixed with down at the root, is employed by 
hatters, like that of the Beaver, and is consequently an important 
article of commerce. Thousands of their skins are imported into 
Europe ” 
Hystrix, Lin. 
The Porcupines are known at the first glance, by the stiff and pointed 
prickles, or quills, with which they are armed, like the Hedgehogs among 
the Carnaria. Their grinders are four throughout, with flat crowns, 
variously modified by plates of enamel, between which are depressed in- 
tervals. Their tongue is bristled with spiny scales, and their clavicles 
are too small to rest upon the sternum and scapula, being merely sus- 
pended by ligaments. They live in burrows, and have many of the habits 
of Rabbits. To their grunting voice, and thick truncated muzzle, are 
they indebted for being compared to the Pig, and for their corresponding 
French appellation of porc-epic. 
PorcupPines, properly so called, 
fiave the head more or less convex or vaulted, by the development of 
2 
