-1KO U. S. F. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



8. CH. Young, dark slaty plumbeous. Adult, yellowish brown ; most usually a broad and well defined dorsal wash of 

 darker. Tail pure white beneath. Tail nearly as long as head and body. Posterior tubercle of sole large, elongated. 

 Roles hairy for less than half their length. Ears with the edge only lighter. Maximum size of bixly, in the llesh, 3. CO ; 

 hind feet, . 75 to . 85. Maximum of skull, 1. 05 inches ; in one instance, 1. 07. 



This animal is considerably larger than the common domestic mouse, the head and body 

 broader also in proportion. The more varied colors, longer and softer fur, larger ears and eyes, 

 and external appearance generally, give to it a much more attractive appearance than that 

 presented by the house mouse. In localities where the latter species has not yet penetrated, it 

 often takes up its abode in dwellings and out-buildings, infesting the premises and doing all 

 the petty mischief for which the other species is so well known. 



The head of this animal is rather broad in proportion to its length. The muffle is entirely 

 hairy to the extremity, both above and below, the septum and region around the nostrils alone 

 being naked. The hair even extends in an obtuse angle a little way on to the septum, but not 

 reaching the level of the nostrils. The nostrils are elliptical, and partly visible from the side. 

 The septum is rather wide, with a single median separating furrow, which passes directly into 

 the deep fissure of the upper lip. This fissure extends as far as the nose, becoming more and 

 more shallow. No traces of cheek pouches can be detected. The ears are large and rounded. 

 There is a long low antitragus, which, however, does not appear at all valvular, as in Jaculus 

 and perhaps Rcithrcdon. It is thinly coated with hairs on both sides, except around the 

 meatus. 



The thumb of the fore finger is a very rudimentary callosity, covered with a broad flat nail 

 exactly resembling that on the human hand. The third finger is longest; the fourth but little 

 shorter ; the second and fifth successively shorter still. The proportions of the hind toes are 

 much like those of the fingers ; the first toe is, however, longer, its claw not reaching quite to 

 the penultimate articulation of the second toe. The palms are naked, with five large nearly 

 equal tubercles, which nearly cover them ; the soles have six tubercles, the anterior five quite 

 similar in size and position to those of the hands, the posterior single one placed a little 

 anterior to a point midway between the heel and the bases of the toes. The soles are covered 

 with short hairs from the heel to near the first tubercle. This character will always serve to 

 distinguish the white-footed mouse from the common domestic mouse, in which the entire under 

 surface of the sole is perfectly naked. 



The tail is a little shorter than the head and body ; very rarely attaining the same size or 

 longer ; it is rounded, tapering to a rather blunt tip ; its surface covered with whorls of scales, 

 between which spring short hairs, partially concealing them ; the tail appearing considerably 

 more hairy than in the domestic mouse. 



The colors of this animal vary very considerably with age. The most perfect pelage of the 

 fully adult specimens is of a light yellowish brown color on the back and sides ; the middle 

 of the back, along a space about the width of the head between the ears, having a wash of 

 darker, owing to a predominance of blackish tips to the hairs ; these tips are also seen on the 

 sides, but in less amount. In some specimens there is a faint indication of a lateral stripe of 

 quite bright rusty yellowish extending on to the cheeks. The under parts and insides of the 

 limbs, with the upper surfaces of the feet, are pure cottony white. The line of demarcation 

 between the colors of the belly and sides commences at the upper incisors, passes backward 

 under the eye, over the shoulders, and along the middle of the sides to the outer edge of the 

 hind legs. The outer surface of the hind legs, exclusive of the feet, is always colored like the 



