Specimens examined, 2: nos. 100628 (the holotype), 6½ mi. W Zamora, 5,950 ft.; 120268 (U. S. Nat. Mus., Biol. Surveys Coll.), Zamora.
Remarks.—When the present account first was prepared our specimen from six and a half miles west of Zamora was tentatively referred to S. h. mascotensis. Subsequently a second specimen, from Zamora, was found. It agreed with the specimen from six and a half miles west of Zamora. Inasmuch as the second specimen agrees with the first and since each of the two differs from any previously described kind, a name and description were published in time to be inserted in the present account. From S. h. mascotensis, S. h. atratus differs in shorter hind foot, darker upper parts, more densely haired tail, shorter skull, more convex dorsal longitudinal outline of skull, posteriorly constricted anterior palatine foramina instead of parallel-sided foramina, and shorter and less decurved anterior process of maxillary arm of zygoma.
Neotomodon alstoni alstoni Merriam
Volcano Mouse; Spanish, Ratón de Los Volcanes
Neotomodon alstoni Merriam, Proc. Biol. Soc. Washington, 12:128, April 30, 1898, type from Nahuatzin, 8,500 ft., Michoacán.
Range.—Higher mountains of state.
Specimens examined, 22: nos. 52179-52184, 52186, 52193-52196, 52199, 52200, 52204-52212, all from Mount Tancítaro, distributed by localities as follows: 7,800 ft., 5; 7,850 ft., 3; 10,000 ft., 4; 10,200 ft., 5; 10,500 ft., 1; 10,800 ft., 1; 11,000 ft., 2; 11,400 ft., 1.
Remarks.—The taking of specimens on Mount Tancítaro extends the known geographic range of Neotomodon approximately 75 kilometers to the southwestward; the westernmost locality previously known was Nahuatzin, the type locality.
Nelsonia goldmani Merriam
Dwarf Wood Rat; Spanish, Rata Montera Minúscula
Nelsonia goldmani Merriam, Proc. Biol. Soc. Washington, 16:80, May 29, 1903, type from Mount Tancítaro, Michoacán.