_Remarks._--There is much variation in size in our animals. The three largest males weigh, in grams, 67.5, 50.3, 48.9 and corresponding figures for the two heaviest, nonpregnant, females are 53.5 and 48.3 grams. Of the 14 adult females, only one was recorded as having embryos; it had two embryos each 24 millimeters in crown to rump length. Where we trapped among big boulders and among the roots of trees of the genus _Ficus_, _Peromyscus banderanus vicinior_ was the only species of the genus taken. _Peromyscus boylii evides_ occurred in the less tropical vegetation, altitudinally and zonally above _P. b. vicinior_. =Peromyscus melanotis= Allen and Chapman Black-eared Deermouse; Spanish, Ratón Montañero _Peromyscus melanotis_ Allen and Chapman, Bull. Amer. Mus. Nat. Hist., 9:203, June 16, 1897, type from Las Vigas, 8,000 ft., Veracruz. _Range._--Higher mountains throughout state. _Specimens examined_, 33: nos. 51397-51401, 52142-52166, 52172-52174, from Tancítaro. _Remarks._--The elevation recorded on the label of one specimen is 9,000 feet and on the labels of other specimens is no lower than 10,500 feet and on some is as high as 12,000 feet. The elevation of capture is not recorded for two specimens. Osgood (1909:112) previously recorded the species from 12,000 feet elevation on Mount Tancítaro. =Oryzomys couesi regillus= Goldman Tropical Rice Rat; Spanish, Rata Arrocera Tropical; Tarascan word for rat is Jeyáquihuiri (Hayakewire), or Sarisi _Oryzomys couesi regillus_ Goldman, Proc. Biol. Soc. Washington, 28:129, June 29, 1915, type from Los Reyes, Michoacán; Goldman, N. Amer. Fauna, 43:37, September 23, 1918. _Range._--Plateau region of Northeast Michoacán. _Specimens examined_, 22: nos. 100601-100622, distributed by localities as follows: 1 mi. N Zamora, 5,450 ft., 2; 4 mi. W Zamora, 5,450 ft., 1; 4 mi. S Pátzcuaro, 7,800 ft., 1; 1 mi. E and 6 mi. S Tacámbaro, 4,000 ft., 18. _Remarks._--The tooth-row is longest in the specimens from Zamora, shortest in those from Tacámbaro and intermediate in length in the one specimen from Pátzcuaro. The shorter tooth-row at the lower elevation (Tacámbaro), we interpret as intergradation with _Oryzomys couesi mexicanus_. In color the specimens from Tacámbaro are, to us, indistinguishable from those from Zamora and Pátzcuaro but the color is notably darker than that of specimens from the vicinity of Apatzingan which are here referred to the subspecies _Oryzomys couesi mexicanus_. The largest male, fully adult from Zamora weighs 82.9 grams and the largest one from the vicinity of Tacámbaro weighs 73.6 grams. =Oryzomys couesi mexicanus= Allen Tropical Rice Rat; Spanish, Rata Arrocera Tropical _Oryzomys mexicanus_ Allen, Bull. Amer. Mus. Nat. Hist., 9:52, March 15, 1897, type from Hacienda San Marcos, 3,500 ft., Tonila, Jalisco. _Oryzomys couesi mexicanus_, Goldman, N. Amer. Fauna, 43:33, September 23, 1918.