186 PROCEEDINGS OF THE ACADEMY OF 



? Mus enroll nensis, And. and Bach., J. A. N. S. P. viii. 1842, 306 ; Q. 



K A. iii. 1854, 332. (South Carolina.) 

 ? Hesperomys cnrolinensis, Wagn., Wieg. Arch. ii. 1853, 51. 

 ? Reithrodon carolinensis, Bd., M. N. A. 1857, 453. 

 Reithrodon 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. Reithrodon longicauda, Baird, M. N. A. 1857, 451. ? Tomes, P. Z. S. 

 1861,284. (Guatemala.) 



Hab. California (? south thence to Guatemala). 



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



Syn. Reitlirodon 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? Ochetodon montanus, (Bd.) Coues. (sp. proband.) 



Syn. 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 ? Ochetodon sumichrasti, (De Saus.) Coues. (sp. proband.) 



Syn. Reitlirodon siimichrasti, De Saus., R. M. Z. 1861, 3. (Mexico.) (Un- 

 known to me.) 



Subfamily Arvicolin^. 



Molars normally rootless, prismatic, with serrate peripherj' and 

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

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

 cess. Descending process of mandible hamular, attaining level of 

 molars. Corouoid a long stout hook. Anterior root of zj'goma 

 not obviously nicked. Palate highly arched. 



Genus V. EVOTOMYS, Coues, n. g. 



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

 1839, 87 (not of 'Ps\\a.%).Hypudwus, Kej-s. and Bias., Wirbelth. 

 1842 (type A. glareola ; not of lUiger, which includes Mus lemmus, 

 amphibins, etc.). Hyjnidceus of Baird, M. N. A., 1857, 513, 515, 

 518 (type A. gapperi). Evotomys, Coues (type 3Iu.s 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 



