Natural History of the Mammalia of India and Ceylon

Family Hystricidæ — The Porcupines

Skull of Porcupine.

In this family the hairs of the body are more or less converted into spines or quills; the form of the skull is peculiar, being ovate, often greatly inflated with air cavities in the bones; the facial portion is broad and short; the malar portion of the zygomatic arch has no inferior angular process as in the Octodontidæ; the occipital plane or hinder-surface is perpendicular, with a median ridge; the incisor teeth are large and powerful; the molars with external and internal folds, four in each jaw. The form is robust; limbs sub-equal; fore-feet with four toes, and a small wart-like thumb; hind-feet with four and five toes; tail long in some, short in others. There are two sub-families—Sphingurinæ and Hystricinæ. With the genera of the first we have nothing to do. They include the prehensile-tailed porcupines of South America, Sphingurus prehensilis, S. villosus, and S. Mexicanus, all arboreal forms, and the Canada porcupine (Erythizon dorsatus) which is covered with woolly hairs and spines intermixed. The true porcupines, sub-family Hystricinæ, consist of two genera, both of which are represented in India—Atherura and Hystrix.