CHINCHILLAS AND VISCACHAS. 169 
Brush-Tailed The brush-tailed poreupines, of which one species (Atherura 
Poreupines. qfricand) imbhabits Western and Central Africa, and the other 
(A. macrura) Burma and the Malayan region, are much smaller and more rat-like 
animals than the true porcupines, from which they are distinguished at a glance 
by their long and scaly tails terminating in a tuft of bristles. The body is covered 
with flattened and grooved spines, which are not much longer on the hind-quarters 
than on the back and shoulders. In the Indian species the length of the head and 
body may reach as much as 22 inches; that of the tail being about 10 inches. In 
colour this species is dark brown, with the tips of the spines sometimes paler. The 
longer spines on the hind-quarters are mostly white; the under-parts, and the 
bristles at the end of the tail, are whitish. 
Gunther's A rare porcupine from Borneo (Trichys quentheri) ditters so 
Porcupine. markedly from the preceding in the characters of its skull, that it is 
regarded as indicating a third genus of the subfamily. It is distinguished exter- 
nally from the brush-tailed porcupines by its shorter spines, and the narrow 
parallel-sided bristles of the tail. 
CHINCHILLAS AND VISCACHAS. 
Family CHINCHILLIDZ. 
The remaining porcupine-like Rodents are contined to South and Central 
America and the West Indies. Those included in the present family are few in 
number, and are characterised by their terrestrial habits, elongated hind-limbs, 
long bushy tails, and extremely soft fur. Internally they have complete clavicles ; 
their molar teeth are divided into a series of parallel transverse plates by the 
extension of the folds of enamel completely across their crowns; and the incisors 
are remarkable for their shortness. In the skull the palate is very narrow in 
front, while behind it remains unossified for a considerable distance in advance of 
the last molar teeth. 
The chinchillas are characterised by having four toes on the hind- 
feet, and five on the fore-feet, by the length of the bushy tail, and 
also by the enormous size of the bulle of the internal ear on the base of the 
skull, which are so much enlarged as to appear on the sides of its upper surface. 
Chinchillas, 
Common The common chinchilla (Chinchilla lanigera) is a squirrel-like 
Chinchilla. Rodent, with very large ears, and a tail about half the length of the 
head and body ; the latter measuring 10 inches. The fur, which is about an inch 
in length, is of extreme softness, and of a delicate pearly grey, mottled with black 
above, and yellowish white beneath; while the tail is mostly black, with lghter 
bands on the sides. The front surfaces of the incisor teeth are of a bright orange. 
This species inhabits the higher Andes, from the south of Chili to the north of 
Bolivia; and in certain districts is very abundant. Chinchillas live in burrows, 
where they associate in large companies, and may frequently be seen abroad during 
the daytime, keeping, however, to the shade thrown by the rocks. On the ground 
they run much after the fashion of mice, but when feeding they sit up on their 
hind-quarters in a squirrel-like manner, and grasp their food between the fore-paws. 
