114 Jlerrkmi — 2\'rir Sjtecies of lliomoniijs. 



Mcnsurcmmts. — Typo specimen ( $ ad.): U)lal len.ylli 21^7: tail vorte- 

 bra' 71: hind loot 34. xVverage of S adults rrom type locality: total 

 len<,'Mi 22S; tail vertebrpe 69: hind foot lil.o. 



Thomomys clusius ocius sp. miv. 



Type from Fort Brid.yer, "Wyoming. No. Hllf- $ *^"1' ^ • ^- National 

 Musenm. Jiioloaical Survey Collection. Maj' 24, 1890. Vernon Hailey. 

 Ori.i-inal No. 1194. 



Cliaracicrs. — Similar lo clusius but slightly smaller and much paler, the 

 npperparts pale butiy: sides of nose and region around moulli dusky 

 plumbeous; cheeks pale butfy gray: sides whitish, tinged with Initfy; 

 feet and underparts white. 



Cranial cliaraders. — Skull like that of clusius but zygomata less sju'cad- 

 ing: temporal ridges a little more strongly ile\elopi'd; inler[)ai'i(Mal 

 larger: bulla* decidedly larger. 



Measuremertis. — Type specimen: total length 201: tail \'erlel)r;r (>(>: hind 

 foot 2(i. Average of 8 adults from type locality; total length I'.i;: tail 

 vertebr;!' 'u: hind foot 2.1. 



Thomomys idahoensis ^p. nov. 



Tyin from ilirch Creek. Idaho. Xo. jofrS, S ad., I'. S. National 

 Museum, Biological Survey Collection. August 8, 1890. C. P. Strealor. 

 Original No. 129. 



Characters. — Size small; coloration pale. Similar in general lo clusius 

 but much smaller and paler. 



Color. — Upperparts grayish butt" strongly washed with buft'y fulvous, 

 often with 'pepper and salt" appearance: underparts, tail, and feel butTv 

 white. 



Cranial clta meters. — Skidl small and rather light, with enormous buihe 

 and narrow zygomata. In general \ike clusiux but much smallei'; bulhr 

 mticli larger and more suollen; nasals long and r;ither slender, with straight 

 sides. 



Measiireirients. — Type specimen: total length 119: tail \ ertebra' 47: hind 

 fodt 2)!. Average of 10 specimens from 1-ype locality: total length 172: 

 tail verlebrje ."il : hind foot 22.5. 



Thomomys desertorum sp. nov. 



Ti^l'e from Mud Si)ring, Detrilal N'alley, Arizona. No. '^iil. c? ad., 

 Merriam Collection. February 21, 1889. A'ernon Bailey. Original No. 

 598. 



Cliaraders. — Size small: coloration buffy or golden fidvons, much as 

 in aureus. Does not re(]uire comparison with any known species. 



