Family IV. Hystricidæ.
(Porcupines.)
Among the Insectivora we found a Family of animals clad in a coat of spiny armour. We are now to consider another group similarly furnished, but in which this defensive array of spines is much more strongly developed than in the Hedgehogs. The Porcupines are covered with a close series of hollow tubes, somewhat like the quills of feathers, usually terminating in a fine point of enamel, of great hardness, but in some instances open at the extremity, as if they had been cut off in their greatest thickness. "The spiny quills of the Porcupine," observes Mr. Martin, "consist of a smooth glossy envelope of horn, and an inner pith, or medullary substance, of a soft texture, and of a pure white. They grow from a bulbous root, formed within a cell below the cutis [or true skin], and containing also a portion of fat, in which the vessels supplying its pulp and capsule are imbedded. The capsules consist of two membranes, of which the innermost secretes the horny envelope, while the pulp supplies the pith of the spine." [1]
The molar teeth are four on each side above and below, furnished with roots, nearly equal in size, nearly round in outline, covered at first with several tubercles, which when worn down present as many oblong layers of enamel on the crown of the tooth, while both the exterior and interior sides are marked by deep folds of the outer coat. The head is short and the muzzle abrupt; the eyes and ears are small, but the nostrils are large and open: the tongue is roughened with scaly prickles directed backwards: the clavicles (or collar-bones) are rudimentary, and hence the forelimbs have not the freedom of motion common to the families we have been considering: their motions are slow and ungraceful, and their form short, thick, and clumsy.
QUILL OF PORCUPINE.
The species of Hystricidæ, though not numerous, are extensively distributed; each great division of the globe has one or more representatives of the family, with the exception of Australia. Most of them are nocturnal animals of sluggish habits, living in burrows which they excavate for themselves. Some species, found in America, climb trees, as the genera Erethizon and Synætheres, the latter of which has the tip of the tail prehensile.
Genus Hystrix. (Linn.)
The Porcupines of the old continent are distinguished by a very convex line of profile, the bones of the nose being much developed. The molar teeth are more elevated above the level of the jaw, and less irregular in their outline, and in the lines of enamel upon their crowns, than those of other genera of this Family. The feet are armed with large nails; the front ones have but four toes each, the presence of a fifth being indicated only by a nail: on the hind feet are five toes. The tail is short, with no prehensile power, clothed with quills open at the end, and, as it were, cut off.
The Common Porcupine (Hystrix cristata, Linn.) is found in Italy, and the North of Africa; but its introduction from the latter country to the former is mentioned by Agricola as having occurred in his time. It is one of the largest of the Rodentia, measuring nearly two feet in length, and some of its longest spines exceed a foot. It is of a dusky black hue, with a whitish band on the neck. On the head is a crest of long pale hair, capable of being erected at pleasure. The back, sides, and hinder parts, are armed with spines, which are very hard and sharp, about as thick as a goose-quill in the middle, furrowed through their length, and marked with broad alternate rings of black and white. They usually lie horizontally, but when the animal is excited (and he is very irritable) a set of muscles beneath the skin erects the spines, which then project stiffly, and present a formidable array which cannot be approached without danger. The animal is said when assaulted to turn his back towards
AFRICAN PORCUPINE.
his enemy, and push against him; and wounds thus inflicted are very severe. The common notion, that it has the power of shooting its spines at an adversary, as a means of defence, though of considerable antiquity, is entirely without foundation.
The strong claws of this animal are of service in the excavation of its burrow, in which it sleeps during the day, coming forth in the evening to feed on roots, fruits, and tender shoots of shrubs. In captivity it is dull, manifesting scarcely a shadow of intelligence.
- ↑ Quadrupeds, p. 154