MAMMALS OF THE MEXICAN BOUNDARY. 423 



bered hills, rising above the general level of the desert basins which 

 make up this tract. 



Descriijtion. — This is the palest subspecies of Peromyscus hoylii, 

 and differs from the more western forms in having the soles of the 

 hind feet naked to the heel. The upper surface is drab-gra}', tinged 

 on sides and rump with ochraceous buff. Ears nearly naked, with a 

 scant hoary pubescence. Tail dusky drab above, pure white below, 

 penicillatc, and rather hairy throughout. Feet and under parts pure 

 white. The coloration is almost identical with that of Peromyscus 

 cremicus arenarius. Length, 202 mm.; tail vertebrae, 115; ear from 

 crown, 14; ear from notch, IS; length of head (nose to occiput), 31; 

 length of hind foot and claw, 22. Skull, 28 by 14. 



Cranial and dental characters. — The skull (fig. 91) is elongated, with 

 the lengthened and depressed rostrum of typical 

 P. hoylii and P. hoylii pinalis, but differs from 

 them in having the nasal bones truncate poste- 

 riorly and ending considerably in front of the 

 posterior extremities of the nasal branches of the 

 premaxillaries instead of terminating in a point 

 well behind them. The dentition (fig. 92) is very 

 different from that of the P. eremicus group, and 

 agrees with the members of the P. leucojnis g^roup 



• ^ 1 ■ 1 • T 1 p ^ ^ p 1 FiG- 92.— Peromyscus 



m havmg a subsidiary loop or fold of enamel boyui penicillatus. 

 between the two principal loops at the outer side crowns of molar teeth 



/. . T P , 1 , , OF TYPE. O, LOWER series; 



or the first and second upper molars. ^ upper series. 



Remarks. — The type was taken in a thicket 

 at the base of a cliff beside the Rio Grande. I saw a similar mouse 

 in Cataract Creek Canyon, Arizona. 



PEROMYSCUS BOYLII ATTWATERI (Allen). 



ATTWATER BRUSH MOUSE. 



Peromyscus nffwateri Allen, Bull. Am. Mu.s. Nat. Hist., VII, Art. X, Nov. S, 1895, pp. 

 330, 331 (original description) ; VIII, Art. V, Apr. 22, 1896, p. 6.5 (Lacey's Ranch, 

 Kerr County, Texas). — Miller and Rehn, Proc. Bost. Soc. Nat. Hist., XXX, 

 No. 1, Dec. 27, 1901, p. 68 (Syst. Results Study N. Am. Mam. to close of 1900).— 

 Elliot, Field Col. Mus., Zool. Ser., II, 1901, p. 135 (Synop. Mam. N. Am.); IV, 

 1904, p, 192 (Mam. Mid. Am.). 



Tyjye-locality. — Turtle Creek, Kerr County, Texas. (Type, skin and 

 skull, in the American Museum of Natural History.) 



Geographical range. — Elevated portions of Middle Texas, in the So- 

 noran zone. Ilills of Kerr and Kinney counties. 



This dark-colored form of Peromyscus hoylii was described by Dr. 

 J. A. Allen from a series of specimens from round about San Antonio, 



b 



