MAMMALS OF THE MEXICAN BOUNDARY. 



269 



General notes.— The subgenus Ar.wosciurus is characteristic of the transition 

 zone in the mountains bordering the table-land of Mexico from Mts. Orizaba 

 and Toluca northward. It is intrusive in the United states, where 11 is rep 

 resented in Arizona and western New Mexico by a single species, 8. arizonensis. 

 The group is most nearly related to Parasciurus, from which the skull charac 

 ters distinguish it. The following species and subspecies belong to tins sub- 

 genus: 8. oculatus, s. o. toluca, 8. alleni, 8. nayaritensis, S. apache, S. anzon- 

 ensis, and 8. a. huachnca. (Proc. Wash. A. -ad. Sri.. I. 1899, p. 29.) 



SCIURUS ALLENI Nelson*. 

 ALLEN SatJIRREL. 



"Sciurus carolinensis??" Baird, Mam. N. Am., 1857, pp. •J';::. 264 (Santa 



Catarina, Nuevo I. con. Mexico). 

 Sciurus carolinensis var. carolinensis, Allen, Mon. N. Am. Etodentia, 1877, 



pp. 706-709, 716 (part: from Nuevo Leon. Mexico). 

 Sciurus carolinensis. ALSTON, Proc. Zool. Soc. London. 1878, pp. 658-659; 



Biol. Cent-Am., Man... pp. 124. 125, June. 1880 (part: from Nuevo 



Leon, Mexico). 

 Sciurus arizonensis, Allen, Bull. Am. Mus. Nat. Hist.. N. Y.. III. -May, 



1891, !». 222 (part: from San Pedro mines. Nuevo Leon. Mexico). 

 Sciurus alien! Nelson, Proc. Biol. Soc. Washington, NIL 1898, pi.. 117. lis. 



June :;: Proc. Washington Acad. Sci., 1. 1899, p. 91, May 9 (Revision 



of the Squirrels of Mexico and Central America).— Millek and Rehn, 



Proc Bost. Soc. Nat. Hist. XXX. PL 1. Dec. 27. 1901, p. 35 (Sysl. 



Results Study X. Am. Mam. to close of 1900).— ELLIOT, Field Col. Mus.. 



Zool. Ser., IV. Pt 1, 1904, p. K»S (Mam. Mid. Am.). 



As long ago as L857 Baird suspected that this species might he dis- 

 tinct from th«' common eastern gray squirrel to which it bears a very 

 close resemblance externally. Lack of material for comparison pre- 

 vented him from naming it. however, and it was first described by 

 Nelson as follows: 



Type-loCality.— MoHtesey, Nuevo Leon. Mexico. Type no. \ )\ \\ O. S. National 

 Museum. Biological Survey collection. 



DistriD uti on.— Open pecan and other forests of Lower Sonoran /.one near 



Monterey, Nuevo I n. extending up to oak and pine forests of Transition zone 



near Victoria and Miquihuana. Tamaulipas. Mexico (alt.. 2,000-8,500 It.). 



Characters.— Upper parts nearly uniform -ravish brown or yellowish brown, 

 much as in Sciurus carolinensis; feet gray; under parts white. Pelage on 

 back soft and rather dense; tail rather full. Teats: p. |. „. |, i. \. 



Color.— Winter pelage: Entire upper parts yellowish brown, finely grizzled 

 with gray and black, usually darker along hack and grayer along sides: top o\ 

 head similar, bul usually a little darker: eye with distinct ring of dingy whitish 

 shaded with huff on outer border; sides of head grizzled dusky gray, often sul 

 fused with yellowish brown; ears and basal paid, brownish gray: fore feet 

 and outside of fore legs whitish gray, frequently more or less washed witb 

 buffy hind feet whitish gray, usually with a spot of dark huffy on middle ol 

 upper surface: outside of thighs like Hanks, hut often with a browner shade 

 near feet ; under parts white; color of upper and lower parts usually separated 

 by a narrow line of pale -ravish: base of tail all around like back; tad above 

 black, heavily washed with white, the yellowish brown or yellowish gray under 



