IS 



fMus carolinemis, Aucl. and Bach., J. A. X. S. P. viii. 1842, 30G ; Q. 



N. A. iii. 1854, 332. (South Carolina.; 

 ? Hesperomys caroUneiisis, Wagu., Wieg. Arch. ii. 1853, 51. 

 ? Reithrodon carolinemiK, Bd., M. N. A. 1857, 452. 

 Beitlirodon megalotis, Bd., M. N. A. 1857, 451 ; Rep. Mex. B. Surv., 



ii. pt. ii. 1859, p. 43, pi. vii. fig. 4 a-c, pi. xxiv. fig. 4 a-g. (Sonora.) 



Hab. United States, southerly. South Carolina to Texas. 

 Kansas. Missouri. Iowa. Nebraska. Utah. Sonora. 



2. Ochetodon longicauda, (Baird) Coues. 



Syn. Ileithrodon longicauda, Baird, M. X. A. 1857, 451.— ? Tomes, P. Z. S. 

 1861,284. (Guatemala.) 



Hab. California (? south thence to Guatemala). 



3. Ochetodon mexicanus, (De Sauss.) Coues. 



Stk. Reithrodon mexicanus, De Sauss., R. and M. Z. 1860, p. — (p. 27 of 

 reprint).— Tomes, P. Z. S. 1861, 284. (Guatemala.) 



Hab. Mexico. Guatemala. Louisiana ? 



4? Oclietodoii montanus, (Bd.) Coues (sp. probnnd.) 



Stn. Reithrodon montanus, Bd., P. A. N S. P. vii. 1855, 335 ; M. N. A. 

 1857, 449, pi. liv. fig. No. 1306 (teeth). (Rocky Mts., lat. 390.) 



5 ? Ochetodoii sumichrasti, (De Saus.) Coues. (sp. proband.) 



Stn. Reithrodon sumichrasti, De Saus., R. ]M. Z. 1861, 3. (Mexico.) (Un- 

 known to me.) 



Subfamily Arvicolinje. 



Molars normally rootless, prismatic, with serrate peripher}^ and 

 flat crowns. Root of under incisor causing protuberance on in- 

 side of jaw at or near notch between condyle and descending pro- 

 cess. Descending process of mandible hamular, attaining level of 

 molars. Coronoid a long stout hook. Anterior root of zj^goma 

 not obviously nicked. Palate highlj' arched. 



Genus V. EVOTOMYS, Coues, n. g. 



Syn. ArvicoJa, sp., Auct. — Myodes, Selys-Lougch., Etudes de Microm. 

 1839, 87 (not of V?iW^%).—nypudceus, Keys, and Bias., Wirbelth. 

 1842 (type A. rjlareola ; not of Illigcr, which includes Mus lemmus, 

 amphibiux, etc.). — Ilypiidceus of Baird, M. N. A., 1857, 513, 515, 

 518 (type A. gapperi). — ^votomys, Coues (type Mus rutilus. Pall.). 



Diag. Dentition arvicoline, in flat-topped prismatic molars, but 

 murine in rooting of the molars (molars only rooted here among 

 Arvicolinse). Coronoid process of lower jaw not attaining level 



