_Range._--Upper Austral and Transition life-zones of Minnesota, northern and western Iowa, southeastern North Dakota, eastern part of South Dakota, and northeastern Nebraska. See figure 29 on page 221. _Characters for ready recognition._--Differs from _M. f. noveboracensis_ and _M. f. primulina_ in that specimens of all ages have least width of color of underparts amounting to more than 41 per cent of greatest width of color of upper parts, and have light color of underparts extended onto hind foot rather than stopped short of ankle; adults with hind feet more than 50 in males and 40 in females; orbitonasal length more than 15.5 in males and 13.5 in females; length of tooth-rows more than 18.0 in males and 15.7 in females; mastoid breadth more than 25.5 in males and 22.0 in females. From _M. f. longicauda_ by color darker than near (_h_) Clay Color, in males by a flattened occiput in which the depth of the skull, exclusive of the sagittal crest and taken at the anterior border of the basioccipital, amounts to less than 58 per cent of the mastoid breadth. _Description._--_Size._--Male: Three adults from Elk River, Minnesota, yield average and extreme measurements as follows: Total length, 458 (444-467); length of tail, 154 (140-165); length of hind foot, 55 (52-59). Tail averages 51 per cent as long as head and body. Length of hind foot averages more than basal length. Corresponding measurements of three subadults from Madison, Minnesota, are as follows: 453 (438-469); 157 (152-165); 50 (47-51). Tail averages 53 per cent as long as head and body. Female: Three adults from Elk River, Minnesota, yield average and extreme measurements as follows: Total length, 387 (380-391); length of tail, 131 (121-138); length of hind foot, 44 (43-46). Tail averages 51 per cent as long as head and body. Length of hind foot more or less than (approximately equal to) basal length. Corresponding measurements of two adults and one subadult from Madison, Minnesota, are as follows: 385 (379-396); 137 (119-159); 42 (38-44). Tail averages 55 per cent as long as head and body. The average differences in external measurements of the two sexes from Elk River, are: Total length, 71; length of tail, 23; length of hind foot, 11. At Madison, corresponding differences are 68, 20, and 8. Two adult females from Elk River, Minnesota, weigh 205 and 210 grams. _Externals._--Longest facial vibrissae black, brown, or white (often all three colors in same specimen) and extending beyond ear; carpal vibrissae same color as underparts and extending to apical pad of fifth digit; hairiness of foot-soles (in summer pelage) as shown in figure 19.