488 U. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



Neatamaflaridana, Aro. & BACH. N. Am. Quad. I, 1849, 32 ; pi. iv. 



KBNNICOTT, U. S. Pat. Rep. 1856, Agricultural, 1857 ; plate . 

 Lcmmus floridanut, FISCHER, Syn. 1829, 299. 



SP. CH. Tail with short stiff hairs, not concealing the ecaly annul! ; about three-fourths the length of the head and 

 body. Ears very large. Feet large. 



(jdar. Above, mixed lead color, dark brown, and yellowish brown ; lighter on the sides. Under parts and feet, white- 

 Tail dusky above, white beneath. Skull elongated and narrow. 



General aspect and dimensions of Norway rat, Mus decumanus. Head rather acute. Whiskers 

 gray and brown, much longer than the head. Eyes moderate. Ears very large, broad, and 

 thin, with very scanty hairs on both surfaces ; naked anteriorly. Antitragus low, narrow. 

 Tail about as long as the body, exclusive of the head, covered with annuli of separate scales, 

 with short stiff hairs springing from under them. These hairs are thick enough to obscure or 

 nearly conceal the scales, which, however, can be discerned through them. The tail is decidedly 

 more hairy than that of the Norway rat. The feet are rather short, the soles naked, although 

 the hairs grow over the sides of the heel almost to the central line. The fur is moderately 

 soft, more so than in the Norway rat, and without the bristly hairs intermixed. 



The tubercles of the sole are very large; of these there is one at the bases of the 3d and 4th, 

 and one, each, to the 1st, 2d, and 5th, making four to the five toes, all nearly equal, the outer 

 one with a small supplementary one on its outer slope ; there is a fifth, of about the same size, 

 near the inner edge of the sole, and situated about midway between the heel and the base of the 

 toes; a sixth, considerably smaller, is placed about midway between this and the large tubercle 

 at the base of the fifth toe, or a little exterior to the line connecting their centre. Most of the 

 sole is naked ; the hairs, however, grow over the inner edge, behind the posterior tubercle, to the 

 middle line of the sole, exterior to which it is naked ; the sides of the tarsus, or heel, are over 

 grown so as to meet in the centre, where the hairs are more sparse ; there is, however, a naked 

 space on the extreme heel. 



These tubercles are much larger than in the house rat; the posterior one is broad and connical, 

 instead of elongated and narrow ; the inner half of the sole, behind the tubercles, with the 

 heel, is hairy, instead of being perfectly smooth, to the very posterior extremity. 



The general color of the upper parts is a dull plumbeous, mixed with dark brown and pale 

 yellowish brown, the latter predominating on the sides, especially on the flanks and in advance 

 of the shoulder ; the dusky of the sides extends down the outer surface of the limbs to the 

 carpus and tarsus, the feet themselves, with the entire under and inner parts, being white. 

 The line of separation of the two colors is far down the sides, so that when viewed in profile 

 but little of the white of the belly is visible. The upper half of the tail is dusky, the lower 

 white. The ears are like the back. The hairs above are plumbeous for the basal three-fourths, 

 then pass gradually into pale yellowish brown, and then tipped with dark brown. The dorsal 

 region is generally decidedly darker than the sides, where the yellowish brown is of greater 

 extent and the dusky tip very slight. Beneath, the hairs along the ventral region are uniform 

 white to the roots ; laterally assuming more and more of a plumbeous tinge. 



Specimens vary considerably with age and season. Sometimes the contrast between the back 

 and sides is more striking, with the more decided yellowish brown tinge on the latter ; at times 

 there is a greater mixture of yellowish brown on the back, producing a strong similarity to the 

 Norway rat. 



In a young specimen, which I refer to this species, collected in Arkansas, by Capt. Whipple, 



