CHINCHILLAS AND VISCACHAS. 169 



Brush-Tailed The brush-tailed porcupines, of which one specie (Atherwra 



Porcupines, africa/na) inhabits 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 (Trickys guentheri) 'lifters 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 Chlyc/iillih. /■:. 



The remaining porcupine-like Rodents are confined 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; ami 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- 



ChinchUlas. J a 



feet, and five on the fore-feet, by the length of the bushy tail, and 



also by the enormous size of the bulla 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. 



common The common chinchilla (Chinchilla lanigera) is a squirrel-like 



Chinchiua. 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 lighter 



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. 



