SACCOMYID^— PEROGNATIIIDIN^— C. FLAVUS. 517 



especially in the frontal region, tapering to a bluntly conical snout, which is 

 densely hairy excepting a minute nasal pad; the upper lip is heavily pilous 

 with a fringe of hairs which droop over and hide the incisors. The eye is 

 rather small, and nearer to the ear than to the nose. Tlie whiskers are very 

 numerous and fine, the longest exceeding the head. On the palms are 

 observed posteriorly two great tubercles, of which the inner is much the 

 largest ; there are others at the base of the 2d and 5th, and of the conjoined 

 3d and 4th digits, respectively; otherwise the palm is studded with minute 

 granulations. The thumb is rudimentary, bearing a small flat nail; the other 

 claws are of ordinary character ; 3d longest; 4th little less; 2d shorter; 5th 

 still shorter. The hairiness of the soles posteriorly is a generic character in 

 comparison with Perognathus ; anteriorly they are granular, with a tubercle at 

 the base of each digit, and another on the outer side of the metatarsus a little 

 way up. The small size of the hind feet, however, is one of the most obvi- 

 ous distinctions from C. parvus. The longest hind foot measured in upward 

 of twenty cases is only 0.70 long, or barely one-third of the length of head 

 and body, while the average is much below this, and the minimum is only 

 about one-fourth of the length of the head and body. We may say simply 

 that the foot is usually nearer one-fourth than one-third of this dimension. 

 Similarly, the shortness of the tail is a second character. In a large series, 

 the vertebrae of the tail average exactly as long as the head and body ; in no 

 case does the tail exceed the body and head by more than 0.25 of an inch, 

 and this length is only exceptionally reached. In most cases, any difference 

 which may be observed is the other way, the tail being, if anything, a little 

 shorter than the head and body. The tail, as in other species of this genus 

 and of Perognathus (except P. penicillatus), is closely, but not very thickly, 

 haired uniformly throughout ; the terminal pencil is about 0.10 of an inch long. 

 The pelage is extremely fine, soft, and glossy. The pattern of coloration 

 is the same as in other species of this genus and Perognathus, namely, col- 

 ored above with blended light and dark tints, white below, with a clear, 

 single-color stripe along the sides. The upper parts are an intimate mixture 

 of pale yellowish-buff with dark brown or blackish ; the hairs are clear lead- 

 color basally, then buff-ringed, then (most of them) dark-tipped. The result- 

 ing tone is nearly uniform over all the upper parts; but there are liable to 

 appear whitish or tawny touches about the ears and eyes, and an appearance 

 of a dark streak aiong the side of the head. The fawn-colored lateral stripe 

 is uninterrupted from nose to heel; the tint is rather brighter than the buff 



