class="x-ebookmaker-pageno" title="[Pg 520]"/>: 1 mi. S Dickinson, 1 (MZ); 9 mi. W Dickinson, 3 (MZ); 2 mi. W Taylor, 4 (MZ). Stutsman County: 7 mi. N Jamestown, 1 (MZ); 14 mi. W Jamestown, 1 (MZ). Wells County: Bowdon, 1 (USBS). Williams County: Buford, 9 (USBS). South Dakota: Todd County: Minichaduza River, 2 (USBS); Rosebud Agency, 1 (USBS). Tripp County: Colome, 3 (MZ). Walworth County: Swan Creek, 13 mi. S Shelby, 1600 ft., 1 (KU).

Perognathus fasciatus olivaceogriseus Swenk

Remarks.—From topotypes of Perognathus fasciatus fasciatus, geographically adjacent to the northeast, P. f. olivaceogriseus differs in: Upper parts paler, especially face which is heavily washed with buff; hind foot smaller; skull averaging slightly smaller in all measurements taken (especially least interorbital breadth and cranial depth), except mastoidal breadth which is slightly more and interparietal breadth, length of tympanic bulla and length of maxillary tooth-row which are approximately the same. From topotypes of Perognathus fasciatus infraluteus, geographically adjacent to the south, P. f. olivaceogriseus differs in: Upper parts paler and less drab; lateral line brighter and more ochraceous; underparts never buffy; skull averaging larger in all measurements taken except interparietal breadth and length of maxillary tooth-row which are smaller. From topotypes of Perognathus fasciatus litus, geographically adjacent to the southwest, P. f. olivaceogriseus differs in: Upper parts darker; skull, when specimens of equal age are compared, averaging larger in mastoidal breadth, interparietal breadth and basal length. From topotypes of Perognathus fasciatus callistus, P. f. olivaceogriseus differs in: Upper parts slightly darker, pelage not silky, coarser in appearance; hind foot shorter; skull averaging smaller in all measurements taken (especially mastoidal breadth), except interparietal breadth which is more.

Swenk (loc. cit.) originally described P. f. olivaceogriseus as a subspecies of Perognathus flavescens. I have examined the holotype, kindly made available to me by Dr. Seth B. Benson of the Museum of Vertebrate Zoology, University of California, and the paratype, in the collection of the University of Nebraska State Museum. Neither is P. flavescens, but both are clearly specimens of P. Fasciatus on the basis of olive-gray dorsal coloration, larger over-all dimensions of the skull, and in that the tympanic bullae do not meet anteriorly. In addition, a third specimen from Glen, Nebraska, purported by Swenk to be intermediate between flavescens and olivaceogriseus, has been examined and found to be an