112 The Wood-Chuck. 



AETICLE Xlll.— On the Wood-ChucTc. [Arctomijs Monax.) 

 GENUS AKTOMYS, Gmel. Cuv. 



DENTAL FORMULA. 



Incisive | ; Canine §={} ; Molar ^^| = 22. 



" Incisors strong, narrow, and wedge-shaped, anterior surface 

 rounded ; molars, with the upper surface thick and heavy. 



" Head large, mouth small, and placed below ; eyes large, ears 

 short, paws strong ; fore-feet with four toes and the rudiment of 

 a thumb ; hind-feet with five toes ; nails strong, compresssd ; tail 

 bushy ; no cheek pouches. 



" The name Arctomys, is derived from two Greek words 

 {arhtoSj) a bear, and [mus,') a mouse. 



" There are as far as we are informed, but eight known species 

 of the genus as it is now defined, five on the Eastern Continent 

 and three in North America. 



ARCTOMYS MONAX.— Linn. 



Wood-Chuck. Maryland Marmot. Ground-Hog. 



characters. 



" Brownish-gray above; head, tail, and feet, dark-brown ; nose 

 and cheeks ashy-brown, under surface reddish. 



DESCRIPTION. 



" The body is thick, and the legs are short, so that the belly 

 nearly touches the ground. Head short and conical ; eais short, 

 rounded, and thinly clothed with hair on both surfaces; eyes 

 moderate ; whiskers numerous, extending to the ear ; a membrane 

 beneath the ears, on the posterior parts of the cheek, and a few 

 setae on the eye-brows ; legs, short and muscular ; fore-feet, with 

 four toes, and the rudiment of a thumb, with a minute nail ; hind- 

 feet, with five toes. Toes long and well separated, pahns naked, 

 with tubercles at the roots of the toes. The middle toe longest — 

 the first and third, which are nearly equal to each other, not 

 much shorter ; the extremity of the nail of the outer, extends only 

 to the base of the nail of the adjoining toe ; fore-claws moderately 

 arched, obtuse and compressed ; the soles of the hind-feet long, 

 and naked to the heel ; hind-feet semi-palmated ; nails channelled 



