1916.] 



GENUS CYNOMYS. 



11 



palm of foot usually extending forward to phalangeal tubercles; 

 manus with, five distinct claws, the claw of pollex weU developed, 

 subequal to claw of outer (fifth) toe. Mammae 8 to 12. Skull 

 rather broad and heavily built ; sinciput high and rounded; squamosal 

 arm of zygoma widely spreading; occipital crest well developed; 

 sagittal crest moderate anteriorly, but well developed posteriorly 

 in old adults; antorbital foramen sub triangular, with strongly devel- 

 oped tubercular process. Molar series strongly convergent posteri- 

 orly; teeth very large and greatly expanded laterally; first premolar 

 large, sometimes nearly equal to second; crown pattern of molars 

 essentially as in true Citellus, but teeth with higher crowns and 

 deeper grooves; molars and premolars with protocone much more 

 hypsodont; with additional transverse ridge extending (from 

 mesostyle) across outer half of center of crown; upper incisors some- 

 times with very indistinct groove along inner face. 



Color pattern. Simple; body unmarked, not sharply bicolor. 

 Upperparts reddish brown, buffy, or grayish, finely lined with darker 

 or lighter hair-tips; underparts paler, clear buff or pale cinnamon. 

 More or less well-marked dark areas above and below eye; tail con- 

 spicuously tipped with black or white. 



GeograpTiic distrihution.—Rockj Mountain and Great Plains 

 regions of the United States and northern Mexico. From the Milk 

 River near the Canadian boundary in northern Montana south to 

 northern San Luis Potosi, Mexico; east to the Missouri River in North 

 Dakota and to about the ninety-seventh meridian in Nebraska and 

 Oklahoma; west to the Rocky Mountains in Montana, to the valleys 

 of central Utah, and to the border of the Grand Canyon on the 

 Hualpai Indian Reservation, Arizona (figs. 1 and 2). 



Remarlcs. — The prairie-dog is a true ground squirrel, or spermophile ; 

 there is no real evidence of the frequently suggested close relationship 

 between Cynomys and Marmota. 



In an article by Prof. K. A. Satunin in the Mitteilungen des 

 Kaukasischen Museums, volume IV, pages 175 to 193, 1909, the con- 

 clusion is reached that Oolohotis Brandt, currently recognized as a 

 subgenus of Citellus, is a synonym of Cynomys. Through the kind- 

 ness of Mr. Oldfield Thomas, I have been able to examine, from the 

 collection of the British Museum, skuUs of the type species of Colo- 

 hotis — Citellus fulvus (Lichtenstein) . It is at once apparent that 

 Cynomys is even less closely related to Colohotis than to Citellus proper, 

 and that it is unquestionably an error to use the generic name Cyno- 

 mys for any of the Old World spermophiles. Colohotis is exceedingly 

 like true Citellus and differs generically from Cynomys in the same 

 characteristics, especially in the less complicated last upper molar, lack 

 of the striking internal hypsodontism of the molariform teeth, and in 

 the nearly parallel-sided palate. 



