304 Br. A. Hall on the Mammals and Birds 



legs short, 4-dactyle and a rudimentary thumb ; hind legs long ; 5- 

 dactyle with nails ; tail long hairy. 



G. Canadensis. Jumping mouse. 

 Dipus Canadensis of Da vies I 

 Dipus Americanus ot^stTlovf \ 

 Mas Canadensis oiVennautl 

 Jaculus Hudsonius ? Baird ! 



v.s.p. Length about the same as common mouse ; head, 

 back, and upper parts of the bo:ly reddish brown verging to yellow ; 

 under parts, as well as the insides of the extremities cream colour ; 

 a yellow streak commences below the nostrils, running along the 

 head and superior and inferior sides of the fore limbs, and thence 

 running along the body terminates at the thighs ; tail much 

 longer than the body ; tapering, ciliated throughout, and termi- 

 nating with a fine pencil of hairs ; slate brown above, cream colour 

 below ; fore feet short, 4-dactyle with sharp nails; hind legs long 

 especially from the heel to the toes, 5 dactyle ; head long, lower 

 jaw projecting beyond the upper. Ears small, oval, whiskers 



long. 



Genus. Arvicola. 



Sub genus. Fiber. 



Sub gen. char. Incisors |, canines none, molars ||=16. Molars 



with flat corners and scaly transverse zigzag lamina ; Fore feet 



4-dactyle with rudimentary thumbs ; hind feet 5-dactyle, edged 



with stiflf and close hairs, and in swimming like the membrane of 



palmated feet. Tail long, laterally compressed, granular. 



F. zibethicus. Muskrat. 

 Castor zibethicus of Linnaeus. 

 Mus zibethicus of Gmelin. 

 Ondathra zibithicus of Say. 



v.s.p. Length of head and body 14 inches, of tail 8f inches ; 

 Fur dark umber brown in the upper part of the head, shoulders 

 ears and back ; the down is dark grey, the tips alone being edged 

 with brown ; sides, breast, fore front of belly and cheeks of a 

 lighter brown hue, while the chin and postarior part of the belly 

 are ash grey ; nose thick and blunt ; ears small ; toes full, the 

 place of web supplied by stiff hairs, which in the hind feet, turn 

 inwards; tail compressed laterally, thin at the edges, covered with 

 scubs and minute stiff appressed hairs of a dusky brown colour, 

 thicker in middle than at the root, and from the middle tapers 

 gradually to an obtuse tip. 



