530 



REPOR T 01'^ STA'I'E (! EO l.0(i 1 ST. 



These mice- are said to have an unusually long i)eri()d of hiber- 

 nation, sometimes remaining dormant until May, although they 

 have also been seen running about during mild winters. Mr. 

 Chansler found one in midwinter near BicknelL hibernating in an 

 underground nest on a side hill near some damp woods. It seemed 

 very stupid and inactive, but ran about some when dug out. 



Their food is said to consist principally of the seeds of grass 

 and weeds. 



The rarity of the species makes it unimportant from an eco- 

 nomic standpoint. 



Family ERETHIZONTIDAE. 



PORCUPINES. 



Rodents with stiff, pointed quills mixed with the fur; feet 

 plantigrade ; toes four in front and five behind ; molars rooted, 

 four on each side of both the upper and lower jaw. 



Porcupines are aften confused, in the popular miind, with 

 hedgehogs. The latter, however, belong to the order Insectivora 

 and are therefore related to the moles and shrews and are limited 

 to the old world. The porcupines, on the other hand, belong with 

 the squirrels, mice, rabbits and other representatives of the Glires 

 or gnawing animals. 



The American porcupines belong to a family distinct from those 

 of the old world. They differ from the latter in lacking a thumb, 

 in having complete clavicles and in several other anatomical de- 

 tails. 



Genus Erethizon F. Cuvier. 



Erefhizon F. Cuvier, Mem. mus. d'hist. nat. Paris, Vol. IX, p. 

 426, 1822. 



Dental Formula.— I, \z\; C, i;-;!; Pm, III';; M, = 20. 



Generic characters. — Tail short, thick and not prehensile; form 

 stout and clumsy; (juills not equalling the hair in length. 



This genus is confined to northern North America, where it 

 lives chiefly in the forests. Two species, each with several sub- 

 species, are recognized. Only one is native to the eastern United 

 States, and it is now extinct in Indiana. 



