70 QUADRUPEDS OF MASSACHUSETTS. 



and formed for jumping ; the former four-toed, and the latter five- 

 toed ; tail long, round, and covered with hair. 



1. Gerbillus Canadensis. Desm. The Jumping Mouse. 



I 



Dipus Canadensis, Davies, Lin. Trans., iv. p. 155. 

 Dipus Americanus, Barlon, Am. Phil. Trans., iv. p. 114. 

 Gerbillus Canadensis, Harlan, Fauna Am., p. 155. 

 The Jumping Mouse, Godman, Nat. Hist., ii. p. 94. 

 Figure ; Ibid., p. 93, f. 1 and 2. 



Specific characters. Head, back, and upper parts of the body 

 reddish-brown ; the under parts, and inside of the limbs yellowish- 

 white, or cream-colored ; tail longer than the body. 



Description. The size of this animal is nearly the same as 

 that of the common Mouse ; the color on the back is a darker 

 brown than elsewhere ; near the lower part of the nostrils there 

 is a band, or yellowish streak, extending the whole length of the 

 head, and the superior and inferior side of the fore limbs ; it 

 passes also along the body, and terminates at the joint of the thighs ; 

 the upper jaw projects beyond the lower ; ears not large, oval 

 and hairy ; mystachial bristles numerous and long ; on the pos- 

 terior extremities the distance from the heel to the toes is great ; 

 the three middle toes are nearly equal in length ; the inner one 

 shortest ; the tail is much longer than the body ; upper sides slate- 

 brown, beneath yellowish cream-color, and terminated with a 

 pencil of hairs. 



FAMILY XL HYSTRICIDiE. The Porcupine Family. 



Genus Hystrix. Lin. 



Generic characters. Dental system ; incisors | ; canines |=^ ; 

 molars |E| ; = 20. Body thick, and covered partly with spines, 

 coarse hair, and fur ; four feet four-toed, and hind feet five-toed ; 

 tail prehensile. 



