Mexican Meadow Mouse; Spanish, Metorito _Microtus mexicanus salvus_ Hall, Univ. Kansas Publ., Mus. Nat. Hist., 1:426, December 24, 1948, type from Mount Tancítaro, 11,400 ft., Michoacán. _Range._--Known only from Mount Tancítaro at elevations of 7,800 to 11,400 feet. _Specimens examined_, 14: nos. 51412, 51413, 52093, 52095-52099, 52101, 52103-52107, all from Mount Tancítaro, distributed by elevations as follows: 11,400 ft., 8; 11,000 ft., 2; 7,800 ft., 1; no elevation recorded, 3. =Microtus mexicanus fundatus= Hall Mexican Meadow Mouse; Spanish, Metorito _Microtus mexicanus fundatus_ Hall, Univ. Kansas Publ., Mus. Nat. Hist., 1:425, December 24, 1948, type from 3-1/2 mi. S. Pátzcuaro, 7,900 ft., Michoacán. _Range._--Central part of state. _Specimens examined_, 59: nos. 100636-100694, distributed, with reference to the town of Pátzcuaro, as follows: 3-1/2 mi. S, 7,900 ft., 9; 4 mi. S, 7,800 ft., 16; 5 mi. S, 7,800 ft., 26; 9 mi. SE, 8,000 ft., 8. _Remarks._--Of the 23 females, only one was pregnant. It had two embryos. Average and extreme weights of ten adults of each sex, are: males, 37.8 (31.5-48.2); females, 38.0 (31.0-48.6) grams. Our specimens were trapped in well-defined runways beneath a rail fence where there was a growth of grass sufficient to make a cover for the runways. Bailey (1900:54-55) has recorded under the name _Microtus mexicanus phaeus_ specimens from Nahuatzin which may be referable to the subspecies _M. m. fundatus_. =Mus musculus= subsp.? House Mouse; Spanish, Ratón Casero _Mus musculus_ Linnaeus, Systema Naturae, ed. 10, 1:62, 1758, type from Upsala, Sweden. _Range._--Probably throughout state. _Specimens examined_, 4: nos. 100696-100699, of which one is from Tacámbaro, 5,700 ft., and 3 are from 4 mi. S and 1 mi. E Tacámbaro, 4,500 ft. _Remarks._--In each of our specimens the belly is dark, approximately as dark as the back. The specimens caught by us were living in the wild; that is to say, they were not caught in and around buildings. Elliot (1903:141) records the species from Pátzcuaro. =Rattus rattus alexandrinus= (Geoffroy) Black Rat; Spanish, Rata Negra _Mus alexandrinus_ Geoffroy, Catal. Mammif. du Mus. Nat. d'Hist., Paris, p. 192, 1803, type from Alexandria, Egypt. _R_[_attus_]. _rattus alexandrinus_, Hinton, Jour. Bombay Nat. Hist. Soc., 26:63, December 20, 1918. _Range._--Probably throughout tropical and subtropical parts of state; recorded also from Pátzcuaro. _Specimens examined_, 3: nos. 52027, 52033 from Tancítaro and 8909 from Pátzcuaro. _Remarks._--These specimens answer well to the description of _R. r. alexandrinus_ except that no. 8909, taken in May, 1901, by F. E. Lutz, has yellowish underparts suggestive of _Rattus rattus frugivorous_. In the town of Tacámbaro we saw a freshly killed rat of this species which was all black. =Sylvilagus floridanus subcinctus= (Miller)