244 BULLETIN NO. VII. 



The porcupines (carefully to be distinguished from hedge- 

 hogs) constitute a small family of rather large, clumsy and 

 indolent rodents which are conspicuous among their fellows 

 for the remarkable change which some of the long hairs un- 

 dergo. These become altered to form sharp quills which 

 usually are so armed with retrorse bristles as to make them 

 very perfect defensive weapons. The body is usually heavy 

 and low, the head short and blunt with heavy muzzle and 

 small ears. The form varies much and, in particular, the tail 

 may be short and bristly, or long, naked and prehensile. The 

 feet have naked soles and usually have the first digit reduced 

 on one or both pairs of limbs. The toes are usually armed 

 with very strong curved claws. The eastern porcupines are 

 terrestrial, living in burrows or cavities in rocks while on the 

 western continent they are more or less arboreal. The food 

 consists of roots, fruits, bark, green leaves and pulpy stalks 

 and, on occasion, almost anything edible. Like most vegetable 

 feeders they are very fond of salt and are as a result of their 

 filthy habits, particularly liable to internal parasites. 



The nasals are frequently very large ; the lachrymal obsoles- 

 cent ; there is no preorbital process of the temporal as in 

 hares ; the zygomas are massive and short. There are four 

 molars in each jaw of similar form and size ; the incisors are 

 large and smooth in front ; the palate is excised between the 

 molars. Malar bone with no angular process below. There 

 are seven cervical, fourteen to sixteen dorsal, five lumbar, 

 three or four sacral and from twelve to thirty caudal vertebrso. 

 The clavicles are poorly developed. There are but four rnam- 

 ms8 in the female. 



The porcupines are brought into relation with rodents in 

 general by a number of South American animals which com- 

 bine the spiny armature with rat-like or hare-like characters. 



The family is very naturally divided into two groups or sub- 

 families as well by the diversity in habits as anatomical differ- 

 ences of the animals inhabiting the two hemispheres. The Hys- 

 tricince, or Old World porcupines, are terrestrial and a number 

 of anatomical peculiarities growing out of this habit are obser - 

 vable. The Synetherince, or American porcupines, are arboreal 

 and thus require more perfect clavicles and ordinarily pre- 

 hensile tails. The molars are rooted while the number of toes 

 is less, the digits being armed with hooked claws which serve 

 in climbing. The soles are tuberculated or roughened. The 



