CLASS I. MAMMALIA: ORDER 7. RODENTIA. 
401 
The Long-tailed Atherure, A. macriirus, the Hystrix Orientalis of Brisson, is found in Ma- 
lacca; it is smaller than the preceding, but has been only obscurely described. The A.Africanus, 
is of Fernando Po, and the A. armatus of Gambia. 
SWInder's aulacodb. 
Genus AULACODE : Aulacodus. — Of this there is a single species, the Ground-Rat or Swin- 
der's Aulacode, a, Swinderianus : this is of the size of a rabbit, of a brown color, with short legs 
and a long body, covered with short spines of nearly uniform length. The tail, of medium length, 
is covered with similar spines. A specimen has been furnished from Sierra Leone to the London 
Zoological Gardens. It is found on the western coast of Africa, and also in Southern Africa. 
Genus ERETHIZON: EretMzon. — Of tbis there is a single species, the Canada Porcupine, 
E. dorsatus ; the Hystrix Hudsonii of Brisson; the Jlrson of Buffon, and the only animal of the 
family of Hystricidce found in North America. In this the ears are short and hid in the fur; 
head, body, legs, and upper part of the tail covered with rather coarse, long, dark-brown hair; on 
the upper part of the head, back, body, and tail, a dense mass of sharp, strong quills, the longest 
on the back, the least toward the head and sides; the longest four inches, but all nearly hid in 
the hair. Intermixed are some stiff, straggling hairs, three inches longer than the rest, tipped with 
dirty white; under side of the tail white; four toes on the fore-feet, five behind, each armed with 
long claws, hollowed on their under side. The form of the body is very clumsy, resembling that 
of a beaver, but in size it is smaller, averaging from tAventy-four to thirty inches. The color, also, 
is subject to great variations, the long hairs on the sides, shoulders, and forehead being sometimes 
of a yellowish-brown, and sometimes of a dirty white. In most cases, however, it anoears that 
the hips and under-surface of the tail, as well as the body, are a blackish-brown. 
The great peculiarity of this animal consists in his spines, or quills, which are cyhndrical in 
shape, sharp at the extremity, and pointed at the root. They are very easily detached, and are 
erected at pleasure. They are barbed with numerous reversed hooks or prickles, which, when 
once the shaft is imbedded in the flesh, constantly work deeper and deeper into it. The spines 
are from one to four inches in length, the longest on the back as above stated. They cover the 
whole upper surface, the under surface being clothed with hair, intermixed with fur of a softer 
texture. In old animals, the whole body above is a mass of spines, with tufts of hair six inches 
long on the shoulders, sides, and forehead. The eyes are small, the tail short, and covered above 
Vol. L— 51 
