MAMMALIA. 409 



** With the tail depressed, and the hairs distichous, 

 Pteromys Sibericus. — Siberian Pteromys. — Plate XV 

 fig. 12 — Fur ash-gray above, white underneath; tail halt' the 

 length of the body. About seven inches long. Inhabits Siberia, 

 Finland, and Lapland. — This is the type of M. F. Cuvier's 

 genus Schropterus. — See vol. II. p. 309, note. 



Section 1 1. — With imperfect clavicles, or none. 



Genus 22 — Hystrix — Linnaeus. 



Generic Character. — Incisory teeth |, no canines, grinders ^— ;• - 

 totol 20. The grinders have Hat tops, but furnished with ridges 

 of enamel. Head strong, convex ; muzzle thick ; ears short and 

 rounded ; tongue furnished with spiny scales ; foi'e feet with four 

 toes, and the rudiment of a thumb ; hind feet with five toes ; 

 the nails on all the feet are strong ; body covered with spines, 

 intermixed with strong hair ; tail more or less long, sometimes 

 prehensile. 



M. F. Cuvier has divided this genus into five distinct genera. 



Hystrix cristata. — The Crested Porcupine. — Plate XVI. 

 fig. 1. — Described, vol. II. p. 354<, &c. 



Hystrix Ciiandu. — The Brazilian Porcupine. — Plate XVI. 

 fig. 2.— Described, vol. II. p. 358, &c. 



This is the type of M. F. Cuvier's genus Sincethere. 



Genus 23. — Atherura Cuvier. 



Generic Character. — Incisors 2, no canines, grinders *-* ; to- 

 tal 20. Head strong, forehead depressed, nearly straight from 

 the occiput to the extremity of the nose ; ears short, rounded ; 

 fore feet with four toes, and a rudimentary thumb ; hind feet 

 with five toes ; nails strong ; tail one-third the length of the 

 body, covered throughout with scales, disposed in rings, tip sur- 

 mounted by a tuft of long flat bristles. 



Atherura fascicuhita. — The Fasciculated Porcupine. — Plate 

 XVI*. fig. 7.— Upper parts of the body, outer sides of the limbs, 

 head, neck, and face, dusky ; under parts, and insides of the 

 limbs, grayish-white, with a darker band crossing the breast, in 

 front of the fore legs ; covered with spines from the back of the 

 head to the root of the tail ; white at their base, and black to- 

 wards their extremity; the upper surface of each with a deep 



