130 A NEW SPECIES OF COTTON BAT—ME IBNS. vol. xvii. 



radically from its geographically nearest neighbors — Sigmodon hispidus 

 Uxiaims, (And. and Bach.) and S. hispidus arizona', (Mearns). 



SIGMODON MINIMA, new species. 



Type.— 1^0. 21187, TJ. S. N. M. (Coll. International Boundary Commis- 

 sion). Adult male, from Upper Corner Monument, New Mexico, on the 

 Mexican boundary line, 100 miles west of the initial monument on the 

 west bank of the Rio Grande. Collected by Edgar A. Mearns and 

 Frank X. Holzner, April 26, 1892. 



Description of type. — Coat bushy and hispid; under-fur darker plum- - 

 beous than in >S'. hispidus tei-ianus or 8. hispidus arizonce; coarse outer 

 coat more bristly, especially on sides of head and neck; ears, feet, and 

 tail densely hairy; tail not distinctly bicolor. Color above grayish, the 

 individual hairs being ringed with gray and brown, the brown annuli 

 being blackish in their middle portion, fading to light-yellowish brown on 

 their edges; under surface of body clayey buff ; feet yellowish gray; 

 ears densely clothed with grayish hairs on inner surface, with their 

 convex surface black anteriorly and buff posteriorly; tail brownish 

 black, somewhat lighter below, the hairs almost concealing the annuli. 



Another specimen (No. 1760, male adult, from the same locality, col- 

 lected by Mearns and Holzner, May 13, 1892) differs only in being 

 ochraceous buff below, with a little more of the fuhous tinge on rumi) 

 and flanks, thus approaching more closely to the coloration of Sigmodon 

 fulviventer. 



Dimensions. — Measurements (in millimeters) of No. 21187, adult male: 

 Length, measured from nose to end of vertebrae of tail, 223 ; tail, measured 

 from root to end of vertebr.c, 94; to end of hairs, 104; height of ear above 

 crown, 14; distance between eyes, 12; diameter of eye, 5; length of 

 longest whisker, 30 ; from tip of nose to eye, 16 ; to center of pupil, 18.5 ; 

 to ear, 30; to tip of ear, 40; to occii)ut, 37; to end of outstretched hind 

 limb, 183; fore limb, measured from olecranon to end of longest claw, 33; 

 length of fore-foot, 15; longest claw of fore-foot (chord), 3.0; hind limb, 

 measured from knee-joint to end of longest claw, 53 ; length of hind-foot, 

 28; longest claw of hind-foot, 3 mm. Measurements of No. 1760, adult 

 male : Length, 223 ; tail to end of vetebrffi, 91 ; to end of hairs, 97 ; height 

 of ear above crown, 12; above notch, 16; distance between eyes, 12; 

 diameter of eye, 5; longest whisker, 26; from top of nose to eye, 16; to 

 center of pupil, 19; to ear, 30; to tip of ear, 46; to occiput, 34; to end of 

 hinder extremity, 180; fore limb from olecranon, 33; length of fore-foot, 

 14; longest claw of fore-foot, 3 ; hind limb from knee-joint, 53; length of 

 hind-foot, 27; longest claw of hind-foot, 4.2 mm. 



Cranial and dental characters. — As compared with S. hispidus texiaiius, 

 the only species before me for comparison, the brain-case is higher and 

 narrower, the skull more constricted between the orbits, with shorter 

 nasals, their bases being nearly even with the posterior border of the 

 incisive foramen instead of well behind it. The dentition is very much 

 heavier- 



