Produced by Chris Curnow, Joseph Cooper, Diane Monico, and the Online Distributed Proofreading Team at https://www.pgdp.net UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY Volume 9, No. 18, pp. 513-518, 1 map January 14, 1960 Conspecificity of two pocket mice, Perognathus goldmani and P. artus BY E. RAYMOND HALL AND MARILYN BAILEY OGILVIE UNIVERSITY OF KANSAS LAWRENCE 1960 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Robert W. Wilson Volume 9, No. 18, pp. 513-518, 1 map Published January 14, 1960 UNIVERSITY OF KANSAS Lawrence, Kansas PRINTED IN THE STATE PRINTING PLANT TOPEKA, KANSAS 1960 28-1243 Conspecificity of two pocket mice, Perognathus goldmani and P. artus BY E. RAYMOND HALL AND MARILYN BAILEY OGILVIE _Perognathus goldmani_ Osgood and _Perognathus artus_ Osgood from southern Sonora, northern Sinaloa and adjoining parts of Chihuahua and Durango, are two named kinds of the _Perognathus intermedius_ group of pocket mice, of the subgenus _Chaetodipus_. Until now the two kinds have been treated in the literature as two species. In both _goldmani_ and _artus_ the upper parts are Ochraceous-Buff (capitalized color terms after Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912) having a strong admixture of black. The lateral line is Ochraceous-Buff, and the underparts are white. _P. goldmani_ is larger than _P. artus_ (see measurements beyond) and has more inflated tympanic bullae and a relatively narrower (transverse to long axis of skull) interparietal bone. Specimens from a transect of southeastern Sonora show intergradation between _Perognathus goldmani_ and _P. artus_. From northwest to southeast the specimens are as follows: one mile east of Buena Vista, on Rio Yaqui Reservoir, 1000 feet (2 specimens, K. U.); Alamos, 1200 feet (7, U. S. B. S.); four and a half miles southeast of Alamos, 1000 feet (5, K. U.); nine miles southeast Alamos, 1000 feet (5, K. U.). The specimens (_P. goldmani_) from Rio Yaqui Reservoir are largest. Those from nine miles southeast of Alamos (_P. artus_) are smallest. Those from Alamos proper are _P. goldmani_. Those from four and a half miles southeast of Alamos (80051-80055 K. U. collected by Robert L. Packard and here referred to _goldmani_) include two as large as _goldmani_ from Alamos, one as small as _artus_ from nine miles southeast of Alamos, and two that are intermediate in size. Features other than size, considered geographically, also suggest intergradation.