616 



MONOGUAPIIS OF NORTH AMKUIOAN RODENTIA. 



i)^ 



llid inniii groove bisects what is Icfl of tiio face of the tooth, nflcr subtnicting 

 tiio portion cut ofT by the inner marginal groove; and this hitter is always 

 distinct. In G. tuza, the main groove divides what is left of the face of the 

 tooth, after subtracting the portion cut off by the inner groove, into two 

 unccpial portions, whereof the exterior is the smaller; and the inner groove, 

 always slight, may be faint, obscure, or perhaps sometimes obsolete. The 

 only other character of G. tuza I can appreciate is the nakedness of the tail 

 and 'eet — especially the former. The species corresponds with G. hvipklus 

 in this respect. In the best-marked cases, the tail is perfectly naked beyond 

 the enlarged hairy base. The hind feet share this nakedness, but not to the 

 same extent ; the instep is nearly bare, but the toes are sparsely pilous with 

 short colorless bristles ; the back of the fore feet is in much the same con- 

 dition. The depilation of the members is not always complete ; younger 

 specimens, in the plumbago state of pelage, show as hairy tail and feet as 

 average samples of G. hursarius. The animal does not differ at all from G. 

 bursarius in size or shape. Under these circumstances, it might be held 

 that the present is merely a localized race of G. bursarius. 



GEOMYS CASTANOPS, (Bd.) LeC. 

 The Fecos, or Chestnut Pocket Gopher. 



r^eudoaloma autanopi, Baird, Stansbnry'i) Bep. Great Salt Lake, 1S69, 313 (uear Benl'H Fort, N. Mex.). — 



Add. & lUcn., Q. N. A. iii, 1854, 304. 

 Geomyt cajtanops, LeC, Froc. Acad. Nat. Sci. Pbila. 185-2, 163.— Baird, M. N. A. 1857, '.181.— Baird, F. R. 



B. Bep. X, 1859, Oannison anil Beckwith's Boate, Mamin. 8, pi. 10, f. 2. — CouES, Proo. Phila. 



Acad. 1875, 133 ; Powell's Bep. Colorado B. 1875, i233 (mono^aphic). — CouES & Yarrow, 



Wheeler's Bep. Expl. W. 100th Merid. v, " 1875" (= 1876), 111. 

 Gcomys clarkii, Baird, Froc. Acad. Nat. Sci. Fhila. 1855, 332 (Texas).— Baird, M. N. A. 1857, 383, pi. 50, 



f. 1 a-ff.— Kennerly, p. R. B. Rep. x, 1859, Whipple's Route, Mamm. 1.3.— Baird, U. S. 



Mex. Bound Survey, ii, pt. ii, 18ii9, Mamm. 41.— Gerk., (^at. Bones Br. Mas. 1862, 222. 

 Chcsinut-fnccd and Pccot Gopher, Baird, U. cc 



Diagnosis. — Superior incisors with a single median groove bisecting the 

 face exactly. Fore feet shorter, or not longer, than hind feet. Feet and tail 

 sparsely pilous. Color pale yellowish-brown above, inclining more or less to 

 dull chestnut about the head ; whitish below. Size of G. bursarius, or rather 

 less. Fur soft, as usual in the genus. 



Habitat. — Texas and New Jlexico. (The few specimens known to 

 naturalists are all from this limited area.) 



(Described from Baird's types of G. castanops and G. "ciarkii", and other 

 specimens.) Distinguished l)y the comi)ination of a single median groove of 

 the incisors, pale light color, and small size. In the first-named particular, 



