470 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



important differences in the size and shape of the post-palatal notch, 

 in the teeth, and in the much greater length of the nasal bones and 

 rostrum. Comparison with the members of the Neotoma fioridana 

 group from the neighboring States — ^Louisiana, Mississippi, Indian 

 Territory, and Kansas — shows it to be a closely related form. The 

 skull, including the teeth, agrees almost exactly with N. fioridana. 

 Externally it differs only in having a softer and finer coat, a much 

 more hairy tail, and a paler and grayer coloration. Members of the 

 fioridana group have been described from Nebraska and Kansas, 

 under the names Neotoma baileyi Merriam" and N. campestris Allen. ^ 

 From these, N. attwateri differs in several minor cranial characters, as 

 well as in the color and texture of the furry coat. It is not improba- 

 ble, however, that all of these forms may prove to be but geographic 

 races of N. fioridana. 



NEOTOMA MICROPUS Baird. 

 TEXAS WOOD RAT; SMALL-FOOTED WOOD-RAT. 



Neotoma micropus Baibd, Proo. Acad. Nat. Sci. Phila., Apr., 1855, p. 333 (original de- 

 'scription; from Charco Escondido, Tamaulipas, Mexico). — Allen, Bull. Am. Mus. 

 Nat. Hist., Ill, 1891, pp. 224, 282 (San Fernando de Presas, Tamaulipas); III, 

 June 30, 1891, p. 282 (species reinstated); VI, May 31, 1894, p. 175 (Aransas 

 County, Texas); VI, Aug. 3, 1894, p. 233, pi. iv (an important paper on 

 "cranial variation in Neotoma micropus due to growth and individual differenti- 

 ation"); VIII, Apr. 22, 1896, p. 60 (Bexar County, Texas). — Merelam, Proc. 

 Acad. Nat. Sci. Phila., 1894, p. 244 (in part ; unites the subspecies carecsceres with the 

 typical form). — Millee and Rehn, Proc. Bost. Soc. Nat. Hist., XXX, No. 1, 

 Dee. 27, 1901, p. 107 (Syst. Results Study N. Am. Mam. to close of 1900). 



[Neotoma] micropus, Elliot, Field Col. Mus., Zool. Ser., II, 1901, p. 155 (Synop. 

 Mam. N. Am.); IV, 1904, p. 281, fig. "xliii" (Mam. Mid. Am.). 



Type-locality. — Charco Escondido, Tamaulipas, Mexico, 62 miles 

 west of Matamoras and 27 miles south of Reynosa. (Type, skull. 

 Cat. No. 1676 — skin missing — , U. S. National Museum.) 



OeograpTiical range. — Inhabits the Texan and Tamaulipan tracts of 

 Mexico and the United States, ranging up the Rio Grande to the 

 mouth of the Devils River. It occupies the lower Sonoran Zone. 



Description. — Size, large; length, 390 mm.; tail vertebrae, 180; 

 hind foot, 40; ear from crown, 25 (measurements of an adult male 

 from Brownsville, Texas) ; skull, 48 by 25 ; color, "slatish gray ' ' above; 

 feet and under surface of head, body, and tail, white; tail, blackish 

 above; ears,, rather small and scantily clothed with a grayish pubes- 

 cence, except on the anterior border of the convex surface, where the 

 hair is longer and blackish. 



Cranial characters. — The skull of this species of Neotoma resembles 

 those of Neotoma leucodon and :A^. cumulator. The orbital margin is 



o Proc. Biol. Soc. Wash., IX, p. 123, July 2, 1894. 

 6 Bull. Am. Mus. Nat. Hist., VI, p. 322, Nov. 7, 1894. 



