MUEIDJE— ARVICOLIISL'E— AEVICOLA XANTHOGNATHUS. 197 



The figures of this series are believed to be approximately correct, 

 though not quite accurate. They indicate an animal at or below the mini- 

 mum of ordinary riparius, with members, especially the tail, below the 

 minimum; the feet, however, do not differ quite so much, being fully within 

 the minimum of riparius, and, in fact, averaging over the dimensions of the 

 average foot of the last table presented, and decidedly exceeding the dimen- 

 sions assigned by Audubon (0.63). As to the form of the thumb-nail, we 

 cannot make out anything at all peculiar. In furriness of pelage, some of 

 these specimens quite come up to the mark of borealis as described. Thus, 

 No. 9235 has the fur on the back fully ten-twelfths of an inch long; and the 

 hair about the lips is so long as to droop over the whole length of the upper 

 incisors, completely hiding them. Then, again, the soles, however, are not 

 nearly so hairy as some other specimens we have seen ; the soles of this same 

 9235 being completely naked from the posterior tubercle. These longest- 

 haired specimens, it should be observed, are all in winter pelage ; spring and 

 summer examples have the fur scarcely, if at all, longer than ordinary Penn- 

 sylvania or Massachusetts skins. 



Different as many of these little creatures look from typical riparius, or 

 from the big ones with which they are associated, it is impossible for us to 

 regard them as specifically distinct. 



ARVICOLA (MYONOMES) XANTHOGNATHUS, Leach. 

 Chestnut-Cheeked Meadow Mouse. 



Arvicola xavthognatha, Leach, Zool. Miscel. i, 1814, 60, pi. 26. — Richardson, F. B.-A. i, 1829, 122. — Add. 

 & Bach. Q. N. A. iii, 1853, 67, pi. 125.-Baihd, M. N. A. 1857, 552.— Dall, Alaska and its 

 Resources, 1870, 577. ( Whether of Sabine 1 Not of any author treating of United States species.) 



Arvicola (J/ yo nomes) xanthognathus, Coues, Proc. Acad. Nat. Sci. Pliila. 1874, 190. 



Diagn. — Arvicola staturd inter maximos, buccis castaneis. 



One of the largest meadow mice, with chestnut cheeks; 5 to 8 inches long; 

 tail 1 or 2 ; hind foot 0.85 to 1.05 ; ear h to f. 



Habitat. — North America, north of the United States. 



Description (No. 4504, Fort Resolution, Great Slave Lake). — This is 

 one of the largest American Arvicola we have ever handled; it measured 6£ 

 inches long when fresh, and the skin indicates a stout, bulky animal. The tail 

 is shorter in proportion than in average riparius; it is said to have been 2.25 

 when fresh, but is now just about 2.00; its hairiness is of medium amount. 



