_Remarks._--The coarse overhair is white all the way to the base in three specimens but is black in its distal two thirds (white in basal third) in four specimens. The overhair, six centimeters anterior to the base of the tail, is 83 (80-85) mm. long in the three gray specimens (those with white overhair) and 68 (64-72) mm. long in the black specimens. The ears and all four feet are black. The tail is black in its proximal half and white in its distal half except in one specimen in which the distal half is almost as dark as the proximal half. Of the two largest specimens, one is a female from 1-3/4 mi. S Tacámbaro and the other, a male is from 6 mi. S of the same place. Measurements are: Total length, [M] 810, [F] 786; length of tail, [M] 360, [F] 348; length of hind foot, --, 58; condylobasal length, 110.0; 99.6; zygomatic breadth, 68.5; 59.6; length of nasals, 59.7, 45.0. The tail amounts to 48, 48 and 47 per cent of the total length in specimens from Pátzcuaro; 50 per cent in one from Tancítaro; 45 and 44 per cent in two from Tacámbaro. The subspecies _mesamericana_ probably intergrades with _Didelphis virginiana virginiana_ by way of _D. m. texensis_ and _D. v. pigra_, as Davis (1944:375) and other writers suggest, in which case the proper name of the subspecies _mesamericana_ would be _Didelphis virginiana mesamericana_. Until intergradation is actually demonstrated, it seems best to use the name _D. m. mesamericana_. Most of our specimens were caught in steel traps, at meat baits, set for small carnivores. =Marmosa canescens canescens= (Allen) Murine Opossum; Spanish, Ratón Tlacuache _Didelphis (Micoureus) canescens_ Allen, Bull. Amer. Mus. Nat. Hist., 5:235, September 22, 1893, type from Santo Domingo de Guzman, Isthmus of Tehuantepec, México. _Marmosa canescens_ Allen, Bull. Amer. Mus. Nat. Hist., 9:58, March 15, 1897. _Range._--Below _Quercus_ belt, probably throughout western half of state. _Specimen examined_, 1: no. 100062, 1 mi. E and 6 mi. S Tacámbaro, 4,000 ft. _Remarks._--The one unsexed subadult measures 5.5 mm. from Ml to M3 inclusive, which measurement is near the minimum that Tate (1933: table 1, Sec. 5) records for this subspecies but larger than the maximum that he (_loc. cit._) records for the subspecies _sinaloae_ which occurs to the northward of Michoacán. Tate (_op. cit._:141) lists two other specimens from Los Reyes. Our specimen was caught in a mouse trap set in dry grass between a sugar cane field and a patch of banana trees. =Sorex saussurei saussurei= Merriam Saussure Shrew; Spanish, Musaraña _Sorex saussurei_ Merriam, Proc. Biol. Soc. Washington, 7:173, September 29, 1892, type from north slope Sierra Nevada de Colima, approximately 8,000 feet, Jalisco. _Range._--In and above _Quercus_ belt, probably throughout northeastern half of state.