_Characters for ready recognition._--Differs: From _M. f. olivacea_, in males, by width of tympanic bulla which is less than rather than more than 8.5 mm., and in adult females by total length which is less than rather than more than 345 mm. and by mastoid breadth which is less than rather than more than distance between articular faces of exoccipital condyle and glenoid fossa; from _M. f. occisor_ by a number of average differences including smaller size, relatively shorter tail and relatively narrower skull (see measurements); from _M. f. spadix_ by least width of color of underparts amounting to less than 41 per cent of greatest width of color of upper parts, absence of color of underparts on ankles and feet, adults with hind foot less than 50 in males and 40 in females, orbitonasal length less than 15.5 in males and 13.5 in females, length of tooth-rows less than 18.0 in males and 15.7 in females, mastoid breadth less than 25.5 in males and 22.0 in females; from _M. f. primulina_ in males by interorbital breadth averaging more than 24 per cent of basilar length, orbitonasal length averaging more than 34 per cent of basilar length or 64 per cent of mastoid breadth, tympanic bullae less inflated anteromedially, than posteromedially, and in females by orbitonasal length amounting to more than two-thirds of mastoid breadth, by zygomatic breadth averaging less than 21, and by anterolateral margin of tympanic bullae not projecting below squamosal; from _M. f. arthuri_ in males, by zygomatic breadth more than distance between anterior palatine foramen and anterior margin of tympanic bulla and by convex dorsal outline of skull in longitudinal axis.
======================================================================= | Number | | |Per cent| | LOCALITY | of | Total | Length | of | Length of | | specimens | length | of tail | body- | hind foot | | averaged | | | length | | ----------+------------+-----------+-----------+--------+-------------+ | 8 ad. [M] | 415 | 146 | 54% | 46.0 | Massa- | | (390-432) | (127-159) | | (41.0-48.0) | chusetts +------------+-----------+-----------+--------+-------------+ | 4 ad. [F] | 311 | 104 | 50% | 33.9 | | | (298-321) | (95-114) | | (31.5-37.0) | ----------+------------+-----------+-----------+--------+-------------+ | 10 ad. [M] | 411 | 141 | 52% | 47.1 | Liberty | | (379-438) | (124-155) | | (43.0-51.5) | Hill, +------------+-----------+-----------+--------+-------------+ Conn. | 6 ad. and | 318 | 105 | 49% | 33.0 | | sad. [F] | (303-338) | (80-123) | | (31.7-36.0) | ----------+------------+-----------+-----------+--------+-------------+ | 10 ad. [M] | 407 | 130 | 47% | 46.0 | Beaver | | (372-431) | (113-143) | | (42.0-50.0) | Dam, +------------+-----------+-----------+--------+-------------+ Wisc. | 4 ad. [F] | 326 | 99 | 43% | 35.6 | | | (303-338) | (86-108) | | (34.6-38.0) | ----------+------------+-----------+-----------+--------+-------------+ | 10 ad. [M] | 371 | 130 | 54% | 45.0 | Washtenaw | | (350-405) | (115-140) | | (40.0-50.0) | Co., +------------+-----------+-----------+--------+-------------+ Mich. | 10 ad. [F] | 306 | 97 | 46% | 34.0 | | | (290-335) | (90-120) | | (30.0-40.0) | ----------+------------+-----------+-----------+--------+-------------+