398 VERTEBRATA. 
Gray. It is readily distinguished by its black color and large size. It inhabits the northern prov- 
inces of Brazil. 
Azara's Agouti, D. A^arce, inhabits Paraguay, Bolivia, and the southern parts of Brazil. 
Waterhouse thinks it identical with Dr. Gray's D. punctata. 
THE PORCUPINE. 
THE PORCUPINES OR HYSTRICIENS. 
This tribe is divided into the Porcujnnes proper and several other groups, which we shall notice 
under their respective generic heads. 
Genus PORCUPINE : Hystrix. — This includes certain rodents whose covering consists for the 
most part of a kind of offensive and defensive armor, in the shape of spines or quills, instead of 
hairs, somewhat after the manner of the hedge-hogs. Their molars are four in number, wdth a 
flattened crown, variously modified by layers of enamel, which leave deep intervals; their tongue 
is rough, with spiny scales ; the tail is short, and the feet plantigrade. Many of the species live 
in burrows, and have much the habits of rabbits. Their grunting voice, joined to their large and 
truncated muzzle, has caused them to be compared to the hog, whence their French name Pore- 
Epic^ ]neaning Spiny-jng. From this we have derived the English name, having a similar sig- 
nification. 
The most celebrated species is the Common Porcupine of Europe, H. cristata^ often called 
the Italian Porcupine, because, at present, it is most commonly found there, and the African 
Porcupine, because the ancients regarded it as having been first brought from Africa to Europe. 
It is called Istrice by the Italians, and Porcopich by the Germans. When full-grown it is about 
two feet in length, the longest spines exceeding a foot. The general color is grizzled dusky-black, 
resulting from an intermixture of various shades of white, brown, and black; upper part of the 
head and neck furnished with a crest of long lighter-colored hairs, capable of being raised or de- 
pressed at pleasure; hair on the muzzle and limbs very short, almost black on the limbs; that of 
the neck and under parts brownish, and of considerable length ; on the fore-part and sides of th(i 
neck a whitish band; all the remaining parts of the back and sides, including the rump and up- 
per parts of the hinder-legs, armed with spines, which are longest on the center of the back. The 
spines, almost of the thickness of a goose-quill in the middle, are supported at the base by a slen- 
der pedicle, and terminating in very sharp points, striated longitudinally, and ringed alternately 
with black and white; the rings an inch or more broad. Their usual position is lying nearly flat 
upon the body, with the points directed backward; when the animal is excited, they are raised 
by means of the subcutaneous muscles almost at right angles w4th the body, and then present a 
