112 



ZOOLOGY. 



Pscwlnstoma nmbrinus, AUD. & BACH., Quad. N. A., iii, 1854, 307. 



Tliomomyx nmbrinun, 15AIKD, Mamin. N. A., 1857, 399. 



Thomomys talpoidcs umbrinm, COUES, Powell's Exp. Col. R., 1875, 2G1 (monographic.) 



Gcomya fidFus, WOODH., Proc. Acad. Nat. Sci. Pbila., 1852, 201 ; Sitgreave's Rep. 



Expl. Znui & Colorado R., 1853, 5L, pi. 5. 



Pseudoatomn (Geomys) fulvus, AUD. & BACH., Q. N. A., iii, 1854, 300. 

 Thotnonu/xfHlPus, BD., M. N. A., 1857, 402; U. S. Mex. B. Surv., ii, pt., 1859, mamm., 



p. . KENN., P. R. 11. lit- p., x, 1859, Whipple's Route, maiiini., 14, pi. 12, f. 



2. COUES, Am. Nat, i, 18G7, 394 ; Proc. Acad. Nat. Sci. Phila., 1867, 135. 



Specimens. 



In these specimens, we recognize fully the Thomomys nmbrinus of Baird, 

 as described at length by that author in the work above quoted. Professor 

 Baird appears to refer the species to the Geomys umbrinus of Richardson 

 with some doubt, in view of certain discrepancies between the subjects of 

 his article and the description of Richardson's a doubt apparently removed 

 by Dr. Coues's article above cited. We present in detail the characters of 

 our specimens. 



The species is among the smaller ones of the genus. Mature specimens, 

 excellently prepared, and thus probably giving reliable measurements, are 

 not over six inches in length from the nose to the root of the tail, which 

 member measures 2J inches. Fore foot, with longest claw, measured from 

 the wrist, \ to \ ; longest claw, about 0.40. Hind foot, with claw, 1 inch, 

 as nearly as possible. Measurements of the head cannot now be well taken ; 

 but the distance from the eye to the ear is about 1, with the eye nearly 

 midway. In form, the species coincides with others of the genus. 



The cheek-pouches, fully everted, are seen to be of a squarish or rather 

 trapezoidal shape, with decided corners, like a small pillow-case. The 

 anterior corner is quite acute; the posterior is more rounded off. The antero- 

 posterior diameter of the pouch is something less than an inch ; its depth 



