The Tree Porcupines, forming the second sub-family, several species with prehensile tails, range over the continent of South America, east of the Andes, and one of them, the Mexican Tree Porcupine (_Sphingurus mexicanus_), is found as far north as Guatemala and Southern Mexico. The most abundant and widely-distributed species in the Brazilian region are the COUENDOU (_Sphingurus prehensilis_) and the COUIY (_S. villosus_), inhabiting Guiana, Brazil, and Bolivia, the latter being found throughout the forest region of Brazil and as far south as Paraguay. These animals are of considerable size, usually measuring from sixteen to twenty inches in length without the tail, which is about one-third the length of the head and body. By the aid of the prehensile tip of this organ they climb with great facility and security upon the branches of the trees, but their feet are also specially adapted for this particular mode of activity, and they are said even to climb the palm-trees in order to feed upon their fruit. They are nocturnal in their habits, passing the day in sleep concealed in the fork of a branch, and going abroad at night in search of their food, which consists of fruits of various kinds, and the buds, leaves, and even flowers, of the trees on which they live. Roots also form a part of their nourishment, probably when they reside rather among thickets than in the high forest. Their spines, although short when compared with those of the Common Porcupine, are formidable defensive weapons when the animal erects them; in some species, as especially in the Couiy, they are concealed, when depressed, by the long hair, and, according to Hensel, this serves as a protection to the animal from rapacious birds, for, when it sits in a heap, sleeping away the daylight, these soft grey hairs give it a most deceptive resemblance to a mass of the beard-moss which so commonly grows on the trees in the Brazilian forests. [Illustration: TREE PORCUPINE.]