116 Merri&m New Species of Thomomys. 



Thomomys limosus sp. no\ . 



Type from White Salmon, Gorge of the Columbia, Washington. No. 

 80,724, $ ad., U. 8. National Museum, Biological Survey Collection. 

 June 2(5, 1897. J. Alden Lor ing. Original No. 4382. 



Characters Similar in size and proportions iodoughm but color much 

 darker; cranial characters distinctive. 



Color. Upperparts dark umber brown; underparts dark slate, the tips 

 more or less deeply washed with buffy or buffy fulvous; feet and tail 

 whitish. 



Cranial characters. Compared with typical douglasi.from Fort Van 

 couver, the xygomata are much more broadly bowed outward and less 

 angular, the nasals slightly constricted behind anterior third and some 

 what expanded and emarginate at posterior end, giving them a 'fish 

 tail' form; interpterygoid space A^-shaped instead of U-shaped: angular 

 process of under jaw decidedly larger and more spreading. 



Measurements. Type specimen: total length 224; tail vertebrae (58; hind 

 foot 30. Average of 4 adults from type locality: total length 210: tail 

 vertebra? 08; hind foot 20. 



Thomomys Hesperus sp. nov. 



Type from Tillamook, Oregon. No. (50,825, 9 ad., U. S. National 

 Museum, Biological Survey Collection. November 0, 1804. ,7. K. 

 McLellan. Original No. 1180. 



Characters. Size small: feet very small (hind foot with claws 24); tail 

 short; ears small; color deep rufous. 



Color. Upperparts deep rufous; nose, earpatch, and ring round eye 

 dusky; underparts varying from buffy fulvous to salmon fulvous; tail 

 dark above, at least on basal half, whitish below and at tip all round: 

 fore and hind feet whitish. 



Cranial character* Skull small and light; interparietal large and 

 broadly sub-triangular; bull;i> small and rounded, short anteriorly; in 

 cisors narrow. 



Remarks. This species differs so markedly from its nearest allies that 

 close comparison is unnecessary. From T\ melanops Merriam from the 

 Olympic Mountains, which appears to be its nearest relative, it differs in 

 much smaller size, strikingly smaller feet and skull; very much nar 

 rower incisors; smaller, shorter, and more rounded bulla 1 ; smaller and 

 narrower basioccipital, much shorter rostrum and nasals, shorter tail, 

 and more rufous coloration. 



Afeasurements. Type specimen ( 9 ad.): total length 175: tail verte- 

 brye 54; hind foot 24. Average of 3 females from type locality: total 

 length 170; tail vertebra.' 51.5; hind foot 24. 



