A specimen from 27 mi. N, 37 mi. E Rock Springs, Wyoming, referred to callistus resembles litus in pale dorsal coloration and slightly wider interparietal. Four immature specimens from 25 mi. N, 38 mi. E Rock Springs, also referred to callistus, have extremely pale juvenal pelage and also are judged to be intergrades with litus.
Specimens examined.—Total number, 23, as follows: Wyoming: Sweetwater County: 18 mi. S Bitter Creek, 6800 ft., 3 (KU); Kinney Ranch, 21 mi. S Bitter Creek, 6800 ft., 9 (KU 7, USBS 2); 30 mi. S Bitter Creek, 2 (KU); 33 mi. S Bitter Creek, 6900 ft., 2 (KU); 32 mi. S, 22 mi. E Rock Springs, 7025 ft., 2 (KU); 25 mi. N, 38 mi. E Rock Springs, 6700 ft., 4 (KU); 27 mi. N, 37 mi. E Rock Springs, 6700 ft., 1 (KU).
TABLE LEGEND:
Column A: Sex and number of individuals averaged or catalog number
Column B: Occipitonasal length
Column C: Frontonasal length
Column D: Basal length[1]
Column E: Mastoidal breadth
Column G: Interorbital breadth
Column H: Interparietal breadth
Column I: Cranial depth
Column J: Length of tym. bulla
Column K: Length of maxillary tooth-row
Symbols:
♂: Male
♀: Female
TABLE 1.—Cranial Measurements of Perognathus fasciatus
| [A] | [B] | [C] | [D] | [E] | [G] | [H] | [I] | [J] | [K] |
| P. f. fasciatus, topotypes | |||||||||
| 6, 4 ♂ and 2 ♀ | 23.35 | 15.55 | 18.4 | 12.3 | 5.3 | 4.9 | 8.7 | 7.3 | 3.3 |
| min. | 22.9 | 14.9 | 17.8 | 12.1 | 5.1 | 4.8 | 8.6 | 7.0 | 3.2 |
| max. | 24.2 | 16.5 | 18.9 | 12.8 | 5.5 | 5.1 | 9.1 | 7.6 | 3.4 |
| P. f. olivaceogriseus, holotype | |||||||||
| ♂ 97941 MVZ | 22.1 | 14.5 | 17.4 | 12.0 | 5.2 | 4.6 | 8.3 | 7.3 | 3.5 |
| Various localities in eastern Wyoming | |||||||||
| 6, 5 ♂ and 1 ♀ | 22.8 | 15.0 | 18.0 | 12.45 | 5.0 | 4.9 | 8.45 | 7.3 | 3.3 |
| min. | 22.2 | 14.5 | 17.5 | 12.2 | 4.9 | 4.7 | 8.1 | 7.1 | 3.3 |
| max. | 23.7 | 15.7 | 18.6 | 13.0 | 5.1 | 5.2 | 8.6 | 7.6 | 3.5 |
| P. f. infraluteus, topotypes | |||||||||
| 4, 3 ♂ and 1 ♀ | 21.9 | 14.4 | 17.3 | 12.2 | 4.9 | 5.2 | 8.2 | 6.9 | 3.4 |
| min. | 21.4 | 14.0 | 17.1 | 11.8 | 4.9 | 4.9 | 8.0 | 6.7 | 3.3 |
| max. | 22.4 | 14.9 | 17.4 | 12.6 | 5.0 | 5.4 | 8.5 | 7.1 | 3.5 |
| P. f. litus, topotype | |||||||||
| ♀ 160599 USBS | 22.2 | 14.7 | 17.4 | 11.9 | 5.0 | 5.0 | 8.7 | 7.0 | 3.3 |
| 8 mi. SE Lost Soldier, 6700 ft., Wyoming | |||||||||
| ♀ 166866 USBS | 22.1 | 14.6 | 17.4 | 12.0 | 5.2 | 4.5 | 8.4 | 7.1 | 3.3 |
| P. f. callistus, Sweetwater County, Wyoming | |||||||||
| 10, 6 ♂ and 4 ♀ | 23.1 | 15.1 | 18.08 | 12.98 | 5.2 | 4.5 | 8.7 | 7.6 | 3.4 |
| min. | 22.7 | 14.7 | 17.5 | 12.7 | 5.0 | 4.1 | 8.5 | 7.3 | 3.3 |
| max. | 24.4 | 15.9 | 18.9 | 13.1 | 5.4 | 4.9 | 8.9 | 7.8 | 3.5 |
[1] Basal length was taken from the anteriormost inferior border of the foramen magnum to the anteriormost projections of the incisors.
LITERATURE CITED
Cary, M.
1911. A new pocket mouse from Wyoming. Proc. Biol. Soc. Washington, 24:61, March 22. 1917. Life Zone investigations in Wyoming. N. Amer. Fauna, 42:1-95, October 3.
Durrant, S. D. 1952. Mammals of Utah, taxonomy and distribution. Univ. Kansas Publ., Mus. Nat. Hist., 6:1-549, August 10.