THE CRESTED PORCUPINE. 
HYSTRIX CRISTATA. Linn. 
Tue entire family of the Porcupines, forming the genus 
Hystrix of Linneus, are at once distinguished from all 
other Rodent animals by the peculiar character of their 
covering, which, instead of being composed of hair 
alone, consists in a great measure of hollow tubes like 
the quills of a bird’s feathers, generally closed at the 
extremity and running out into a fine point, but some- 
times truncate and open. They have all four cheek 
teeth on each side of either jaw, furnished with distinct 
roots, nearly equal in size, irregular but somewhat 
circular in outline, and presenting in the young state 
on the surface of their crowns several tubercles of 
various size and form. As the teeth are worn down in 
advancing age, these tubercles give rise to as many 
elliptical layers of enamel occupying the centre of the 
tooth, while its circumference is marked, both internally 
