THE COMMON MEADOW MOUSE. 15 



slope. In autumn, shortly before the first snowfall, the Eskimo 

 women and children discover these stores by means of pointed sticks. 

 In this way considerable quantities of food are gathered, which are 

 boiled and eaten as a delicacy. " The boiled roots have a flavor like 

 a boiled unripe sweet potato, and are very palatable during the long 

 winter fare of meat and fish." a 



THREE TYPICAL SPECIES. 

 I. THE COMMON MEADOW MOUSE. 



Microtus pennsylvanicus (Orel.) (PI. I, fig. 1). 



The most familiar of American species of Microtus is the common 

 meadow mouse (31. pennsylvanicus) . The average measurements of 

 adults are about as follows: Total length, 170 mm. (6.6 inches) ; tail 

 vertebrae, 46 mm. (1.8 inches) ; hind foot, 21.2 mm. (0.83 inch). The 

 tail is always at least twice as long as the hind foot. The fur is long 

 and overlain with coarse black hairs. In summer the ears overtop 

 the fur. In winter the fur is longer, of a duller color, and almost 

 conceals the ears. The usual color above is a dark brown, against 

 which the black hairs are not conspicuous. This shades off gradually 

 into gray or tawny on the under parts. The feet are small, the claws 

 on the hind feet slightly larger than those on the front. The foot 

 pads are 6; the mammae 8 (1 pectoral and 1 inguinal). 6 



The vast range of this species has already been given. This 

 mouse has its natural habitat in moist meadows and grassy borders of 

 swamps, but it habitually extends its range into neighboring culti- 

 vated fields, waste lands, and open spaces on the border of timber 

 lands. Wherever it occurs, it is normally the most abundant rodent. 

 Nearly all meadows are full of the animals. On parting the thick 

 grass almost anywhere one can find the smooth trails, and where the 

 grass is thin they are often plainly visible. After the melting of 

 deep snow, or where the dry grass has been burned, the network of 

 runways is especially conspicuous to the eye. In swamps the paths 

 cross soft mud and standing water, if shallow. When green scum, 

 composed of minute floating plants, covers stagnant water, the trails 

 are defined across it by streaks of clear water where the animals swim 

 from side to side in the pools. In walking across a swamp one some- 

 times frightens them from the shelter of tussocks and sees them 

 swim away or run through shallow water. 



In swamps meadow mice nest in burrows in dry tussocks or in 

 bunches of grass above the surface of the moist ground. The nests 

 are composed of grass or fibers of weeds made into balls, loose and of 



« Proc. Wash. Biol. Soc, vol. 8, pp. 139-142, 1895. 



6 For dental and skull characters consult N. A. I'auna No. 17. p. 17, 1900. 



