296 PROCEEDINGS OF THE ACADEMY OP 



quite to the heel ; the antitragus has a very prominent lobe ; and 

 even from the dried skins I determine, with no appreciable chance 

 of mistake, that the ear has the other peculiarity of P. monticola. 

 The pelage is remarkably soft ; the coloration is different from that 

 of any other Perognathus I have seen, being plumbeous (like the 

 plumbago-colored specimens of Geomys and Thomomys), with 

 little admixture of lighter color ; and the soles show a decided 

 fulvous stripe. But these specimens exhibit the fore leg colored 

 quite to the wrist, and I am inclined to attribute the dark color 

 to their immaturity. I shall therefore assign them to P. monti- 

 cola. 



The four specimens noticed are the only ones which have come 

 under my observation. To sum the casein a few words, we have 

 here an animal unquestionably distinct from any of the other spe- 

 cies described in this paper, the only question being whether all 

 the specimens referred to it are specifically identical. They os- 

 tensibly differ to a degree that would undoubtedly have caused 

 them to be described as two or three species at the period when 

 Prof. Baird's work was prepared. This question must await the 

 reception of additional material for its satisfactoiy solution. I 

 can only say that I am at present unable to see more than one 

 species. Should the contrary be determined, the present article 

 is to be held as based upon the Fort Crook specimen, to which 

 the name of P. mollipilosus may be applied. 



Perognathus hispidus, Baird. 



Perognathus Mspidus, Baird, M. N. A. 1857, 421, pi. 51, fig. 4 a-g. Baird, 



U. S. and Mex. B. Surv. ii. pt. ii. 1859, Mamm. p. .Gray, P. Z. S. 



18G8, 202 (compiled). 



Diagn. Ear small, not projecting beyond the fur; its structure 

 as in P. fasciatus and iienicillatus (tragus and antitragus both 

 lobed). Soles naked. Tail not penicillate, rather longer than 

 head and body. Fur exceedingly stiff and coarse. Above yel- 

 lowish-cinnamon, closely lined with blackish, the color not de- 

 scending on the fore leg at all. Sides with a conspicuous fulvous 

 stripe. Tail bicolor. Under parts, with hind feet and whole of 

 fore leg, white. Length between 3.00 and 3.50; tail, rather more. 

 Sole of hind foot 0.90. 



Hab. The only two specimens known of this species were pro- 

 cured by Lt. Couch at Charco Escondido and Matamoras, Tamau- 

 lipas. 



