406 Mr. O. Thomas on a new Species o/" Perognathus. 



tlie others, and, so far as I can make out, not referable to any 

 hitherto known species. It may be termed 



Perognatlms infraluteuSj sp. n. 



Size small, about as in P. lo»glmcmhris. Pelage soft. 

 General colour above tending towards greyish olivaceous, 

 decidedly more so tlian in P. fiavii.tj but less than in P. Lordi. 

 Lighter patches behind ears much reduced, scarcely percep- 

 tible ; ears very small (but doubtiully quite perfect in the 

 type), their infolded edges yellowish. Fulvous lateral band 

 strongly defined from the dark upper surface, but extending 

 beneath the body so as to cover the whole under surface 

 exce])t just the throat and the centre of the neck and breast ; 

 the limbs also wholly fulvous; the hairs of this fulvous 

 underside every where slaty grey for their basal halves. This 

 coloration, strikingly different as it is from the usual pure 

 ■white under surface, seems to be only paralleled by that of 

 Dr. Merriam's P. olivaceus amrjnnus, a very much larger 

 animal. Soles liairy for their posterior half. Tail short- 

 haired throughout, yellowish above, whitish below. 



Skull of about the size and proportions of that of P. longi- 

 memhrisj but the mastoids are markedly less swollen, do not 

 approach each other so much, and do not project backwards 

 beyond the level of the occiput. The interparietal is conse- 

 quently much broader, although of the usual length ; it is in 

 fact '' broadly pentagonal," ratio of length to breadth 53 per 

 cent. Frontal, median, and mastoid sides of parietals sub- 

 equal and longest, about 4 millim. each. 



Teeth. — ?y very small, scarcely larger in section than the 

 rounded anterior cusp of the premolar. Lower premolar 

 rather larger than ^75, rounded quadrangular, its posterior 

 side the longest. 



Dimensions of the type (an adult female) : — 



Head and body (measured in flesh by collector) 60 millim.; 

 tail 57 ; hind foot, without claw (camped and measured in 

 skin) 14'9, with claw 16 ; hairy part of sole in centre 66. 



Skull: basal length 17'3; basilar length of Ilensel L5"3 ; 

 greatest median length 2\'2; greatest mastoid breadth ll'l ; 

 nasals, length 7"7; interorbital breadth 4*9; interparietal, 

 length 27, breadth 5"1 ; least distance between mastoids 

 above 5*2; combined lengths of three upper molars 1*9; 

 ditto, three lower molars, 2'2. 



Uah. Loveland, Larimer County, Colorado, 5000 feet. 

 Coll. W. G. Smith, Ainil 4, 1892. 



This species is perhaps most nearly allied to P. fasciatus, 

 Wied, from Montana, but it is readily distinguishable by its 

 difffvput coloration and somewhat smaller size. 



