22 



Armcola modesta, Bd., op. cit. 535. (Rocky Mts.) (Very young.) 

 Arvicola rufidorsum, Bd., op. cit. 526. (Mass.) (Reddish specimen.) 

 Arvieola breweri, Bd., op. cit. 525 (Muskeget, Mass. ; bleached insular 

 race). 



Ifl. Arvieola (riparius var. ?) borealis, Rich. ? 



Syn. ? Arvieola borealis, Rich., Zool. Journ. 1828, 517 ; F. B.' A. i. 1829, 

 127. — Also of Aud. and Bach., and of Baird. 



Hah. Northwestern America. 



Obs. This and the two succeeding species are presented provi- 

 sionally. 



2. Arvieola (Myonomes) townsendii, Bach. 



Syn. Arvieola townsendii, Bach., J. A. N. S. P., viii. 1839, 63, and of 

 subsequent writers. 

 Hah. Oregon and Washington Territories. 



3. Arvieola (Myonomes) xanthognathus, Leach. 



Syn. Arvieola xanthognatha, Leach, Zool. Misc. i. 1814, 60, pi. 26. — 

 Rich., F. B. A. i. 1829, 122.— Aud. and Bach., Q. N. A. ill. 1853, 

 67, pi. 125.— Bd., M. N. A. 1857, 552.— Dall, Alaska and its Re- 

 sources, 1870, 577.— Whether of Sabine ? but certainly not of any 

 author treating of United States species. 



Hah. British America. 



Obs. In its typical condition the animal is unmistakable in its 

 immense size (up to 8 inches long) and chestnut cheeks. There 

 remain, however, some points to be elaborated before the relation- 

 ship of the several forms of Myonomes can be considered estab- 

 blished. 



Subgenus Chilotus, Baird. 

 Syn. Chilotus, Baird, 1857. Type, A. oregoni. Bach. 



4. Arvieola (Chilotus) oregonus, Bach. 



Syn. Arvieola oregoni, Bach., J. A. N. S. P., viii. 1839, 60.— Aud. and 

 Bach., Q. N. A. iii. 1853, 232, pi. clxvii. f. 3.— Bd., M. N. A., 1857, 

 537. . 



Hah. Oregon. 



Subgenus Pedomys, Baird. 

 Syn. Pedomys, Bd., M. N. A. 851, 517. Type, A. atisterus, LeC. 



5. Arvieola (Pedomys) austerus, Le C. 



Syn. Arvieola austerus, J^e C, P. A. N. S. P. vi. 1853, 4t35. ("Wiscon- 

 sin.) 

 Arvieola (Pedomys) atisterus, Bd., M. N. A. 1857, 532, pi, liv. (Wis- 

 consin and Missouri to Louisiana.) 



