| Number of individuals averaged of each sex or specimen measured | Total length | Tail | Hind foot | Condy- lobasilar length | Zygomatic breadth | Lambdoidal breadth | Length of nasals | Alveolar length of upper tooth- row | Breadth of rostrum | Length of incisive foramina | Height of skull |
| Clethrionomys gapperi solus, Loring | |||||||||||
| ♂type | 133 | 33 | 20 | 22.3 | 12.5 | 10.9 | 6.8 | 5.1 | 3.4 | 5.3 | 9.0 |
| ♂ 5 av. | 131 | 34 | 20 | 22 | 12.7 | 10.8 | 6.8 | 5.3 | 3.5 | 5.1 | 9.1 |
| min. | 128 | 33 | 19 | 21.8 | 12.5 | 10.5 | 6.7 | 5.1 | 3.3 | 5.0 | 8.9 |
| max. | 133 | 36 | 20 | 22.3 | 13.0 | 11.2 | 7.1 | 5.5 | 3.6 | 5.3 | 9.5 |
| ♀ 5 av. | 128 | 34 | 19 | 21.3 | 12.5 | 10.5 | 6.5 | 5.4 | 3.5 | 4.9 | 9.2 |
| min. | 124 | 31 | 19 | 20.9 | 12.3 | 10.3 | 6.0 | 5.2 | 3.3 | 4.8 | 8.9 |
| max. | 140 | 36 | 20 | 21.7 | 12.7 | 10.7 | 7.0 | 5.6 | 3.6 | 5.0 | 9.5 |
| Clethrionomys gapperi stikinensis, Stikine River at Great Glacier | |||||||||||
| ♂ type | 145 | 39 | 20 | 23.2 | 13.9 | 11.4 | 7.3 | 5.0 | 3.1 | 5.5 | 9.5 |
| ♂ 4 av. | 136 | 5 | 20 | 22.2 | 13.0 | 11.1 | 6.8 | 5.2 | 3.4 | 5.2 | 9.4 |
| min. | 132 | 33 | 19 | 21.5 | 12.3 | 10.7 | 6.5 | 5.0 | 3.1 | 5.1 | 9.1 |
| max. | 145 | 39 | 20 | 23.2 | 13.9 | 11.4 | 7.3 | 5.6 | 3.5 | 5.5 | 9.7 |
| ♀ 7 av. | 134 | 33 | 19 | 21.8 | 12.76* | 10.9 | 7.0 | 5.4 | 3.4 | 5.1 | 9.5 |
| min. | 125 | 30 | 19 | 21.5 | 12.5 | 10.5 | 6.7 | 5.3 | 3.2 | 5.0 | 9.2 |
| max. | 147 | 35 | 20 | 22.2 | 12.9 | 11.3 | 7.1 | 5.6 | 3.7 | 5.3 | 9.8 |
| Clethrionomys gapperi wrangeli, Wrangell | |||||||||||
| ♂9 av. | 139 | 36 | 19 | 23.48 | 13.3 | 11.48 | 7.3 | 5.6 | 3.6 | 5.6 | 9.68 |
| min. | 130 | 31 | 18 | 22.9 | 13.0 | 10.9 | 7.1 | 5.5 | 3.3 | 5.4 | 9.2 |
| max. | 151 | 43 | 20 | 23.9 | 13.7 | 11.8 | 7.6 | 5.8 | 4.0 | 5.8 | 10.1 |
| ♀ 16 av. | 134 | 34 | 1815 | 23.2 | 13.3 | 11.213 | 7.3 | 5.8 | 3.5 | 5.5 | 9.4 |
| min. | 123 | 28 | 17 | 22.4 | 12.6 | 10.7 | 6.9 | 5.5 | 3.2 | 5.2 | 9.0 |
| max. | 156 | 45 | 20 | 24.1 | 14.1 | 11.8 | 8.0 | 6.1 | 3.7 | 5.9 | 9.7 |
| Clethrionomys gapperi phaeus, Chickamin River | |||||||||||
| ♂ 5 av. | 148 | 47 | 20 | 23.04 | 13.74 | 11.34 | 7.54 | 5.34 | 3.54 | 5.34 | 9.73 |
| min. | 138 | 38 | 20 | 22.3 | 13.0 | 11.1 | 7.1 | 5.3 | 3.4 | 4.9 | 9.3 |
| max. | 159 | 51 | 21 | 23.8 | 14.6 | 11.8 | 7.7 | 5.6 | 3.8 | 5.6 | 10.0 |
| ♀ 4 av. | 153 | 49 | 20 | 23.13 | 13.4 | 11.23 | 7.63 | 5.2 | 3.7 | 5.3 | 9.63 |
| min. | 140 | 44 | 20 | 22.4 | 12.8 | 10.8 | 7.3 | 5.0 | 3.4 | 5.1 | 9.2 |
| max. | 164 | 56 | 20 | 24.2 | 13.6 | 11.4 | 7.7 | 5.3 | 3.9 | 5.5 | 9.8 |
*Superior numbers denote the number of individuals averaged.
Measurements.—External and cranial measurements of adults are given in table 1.
Remarks.—Morphologically C. g. stikinensis shows greater resemblance to C. g. solus of Revillagigedo Island, than to the geographically adjacent subspecies C. g. wrangeli and C. g. phaeus. Possibly the original stock of C. g. solus was rafted to Revillagigedo Island from the Cleveland Peninsula.
Specimens examined.—Total, 29, all in the Museum of Vertebrate Zoology, University of California, distributed as follows: British Columbia: Stikine River at Great Glacier, 22; Stikine River at Flood Glacier, 3. Alaska: Bradfield Canal, 1; Helm Bay, 2.
Pitymys pinetorum scalopsoides (Audubon and Bachman)
1841. Arvicola scalopsoides Audubon and Bachman, Proc. Acad. Nat. Sci. Philadelphia, 1:97, type from Long Island, New York.
1912. Pitymys pinetorum scalopsoides Miller, U. S. Nat. Mus. Bull., 79:229, December 31.
Hanson (Trans. Wisconsin Acad. Sci., Arts, and Letters, 36:124, 1944) reported two pine mice from near Prairie du Sac, in Westpoint Township, Columbia County, Wisconsin, as Pitymys pinetorum scalopsoides but cast doubt upon their subspecific identity. He also reported pine mice from Blue Mounds, Dane County, Wisconsin. We have examined these specimens (Westpoint, Columbia County, 2—No. 544, skin only, UWDEZ, and No. 521, skin only, H. C. Hanson's private collection; Westpoint, Dane County, 1, No. 11620, UWZM; Vermont, Dane County, 2, Nos. 11674 and 11694, UWZM) and have compared them with topotypes of P. p. schmidti, and with specimens of P. p. nemoralis and P. p. scalopsoides. The specimens from Columbia and Dane counties differ from P. p. schmidti in the greater zygomatic breadth, and lesser height of skull. They differ from P. p. nemoralis of comparable age in shorter tooth-row and generally smaller skull. The interorbital region, however, is wider. In all of the features mentioned above, the specimens in question agree with Pitymys pinetorum scalopsoides, to which subspecies they are here referred.
Microtus pennsylvanicus aztecus (Allen)