NO.1103. PBOCEEDIKGS OF THE NATIOXAL MUSEUM. 139 



PEROMYSCUS BOYLII PENICILLATUS, new subspecies. 

 BAREFOOTED BRUSH MOUSE. 



Ti/2)e.—:^o. UHh U.S.N. M. (Coll. International Boundary Commis- 

 sion). Adult female, from the footliills of the Fraukliu Mountains, near 

 El Taso, Texas. Collected by Edgar A. Mearns and F. X. Holzner, 

 February 19, 1892. Original number, 14(53. 



Description of type. — Above drab-gray, tinged with ochraceous buff 

 on sides and rump. Ears nearly naked, with a scant hoary pubescence. 

 Tail dusky drab above, pure white below, penicillate, and rather hairy 

 throughout. Feet and under parts pure white. Length, 202 mm.; 

 tail vertebrne, 115; ear from crown, 11 (from oriilce, 18); distance 

 between eyes, 12; diameter of eye, 4; length of longest whisker, 47; 

 from tip of nose to eye, 10; to center of pupil, 19.5; to ear, 28; to end 

 of outstretched hind limb, 143; to occii)ut, 31; fore limb, measured 

 from olecranon process to end of claws, 24: length of manus, 11; long- 

 est claw of manus, 2; hind limb, measured from knee Joint to end of 

 claws, 45; length of hind foot with claw, 22; longest claw of hind foot, 

 2.5. Skull, 28 by 14 mm. 



CraniaJ (dkJ denidl eJiaraeter.s. — The skull is elongated, with the length- 

 ened and depressed rostrum of P. boylii and P. hoyJii pinaJis, but dif- 

 fers from them in having the nasal bones truncate posteriorly and end- 

 ing considerably in front of the posterior extremities of the nasal 

 bi'anches of the premaxillaries, instead of terminating in a point well 

 behind them. The dentition is very different from that of the eremicus 

 group, and agrees with the members of the P. leiicopus group in having 

 a subsidiary loop or fold of enamel between the two princii)al loops at 

 the outer side of the lirst and second up])er molars. 



The species to which this Brush Mouse belongs [FeromyHCus hoylii.^ 

 Baird) is evidently the connectant between the wood mice (J*. Icucopus 

 group) of the East and the desert mice (P. cre)nicus group) of the 

 West. The si\bs])eGie» pe^ii cilia tus has the tail as long and soles as 

 bare as those of P. eremicus arenariiis of the same region ; its coloration 

 is almost identical; and it has the same posteriorly truncate nasals and 

 large, nearly naked ears. It agrees with J', leucopus in having a hairy 

 tail and the more complicated enamel folds in the first and second 

 upper molar teeth described above. The western forms of the Brush 

 Mouse (P. boylii, P. h. roirleyi, and P. h.pinalis) have pointed nasals — 

 much as in Onyrhomys — and hairy heels. 



ONYCHOMYS TORRIDUS ARENICOLA, new subspecies. 

 EL PASO GRASSHOPPER MOUSE. 



Type.—^o. f His, U.S.KM. (Coll. International Boundary Commis- 

 sion). Adult male, from the Bio Grande, about six miles above the 

 town of El Paso, Texas. Collected by Edgar A. Mearns and F. X. 

 Holzner, February 29, 1892. Original number, 1528. 



Description of type. — Similar to OnycJionn/s torridns, but slightly 

 smaller, with relatively smaller ears, and a very much paler coloration. 



