259 



-exposed parts of the front of the ear being more thickly clothed. The 

 antitragal pad bears on its outer surface a special tuft of long- hairs ; its 

 other side being naked, as are both sides of the flap of the tragus. 



The fore limbs are absolutely small as well as short relatively to the 

 hinder ones ; and they seem to be placed rather far forward, though this 

 appearance may be due, in part at least, to the tapering shape of the 

 body. The hands are pilous above, naked below. There are four per- 

 fect fingers, with ordinary claws, and a rudimentary thumb, which bears 

 a flat, blunt nail. The third digit is the longest ; the fourth, second, and 

 fifth being successively shortened. The digits are regularly transversely 

 scutellate below. The palm is granular throughout, with a pair of large 

 smooth pads (inner and outer) near the wrist, and three smaller tuber- 

 cles at the base of, respectively, the second, the fifth, and the conjoined 

 third and fourth digits. 



The elongation of the hind limbs, which confers the high degree 

 of saltatorial power upon this animal, like that of Bipus, &c., to 

 which it has been referred, is especially noticeable in the pes, which eJc- 

 ceeds the crns in length. This development of the foot, nevertheless, 

 is not accompanied Iby reduction of the digits in number, nor by any 

 imperfection of their respective metatarsals. The number of these bones 

 has been queried ; I find five, perfect from end to end, with complete 

 tarsal and phalangeal articulations. The foot is clothed above with short, 

 soft, silky hairs, quite different from the hirsute pelage of the body; 

 below it is entirely naked, though the lateral fringe of hairs encroaches 

 upon the contracted heel. The sole is perfectly smooth (as in BIus) for 

 about half-way, then granular; the digits are transversely scutellate 

 underneath. There is a well-detiued tubercle on the inner side a little dis- 

 tance above the base of the first digit, and four others at the bases of, re- 

 spectively, the first, second, fifth, and conjointed third and fourth digits. 

 There are five perfect and normally-clawed digits. The first is shortest, 

 and also situated rather high up, so that its tip reaches only to about 

 the base of the second. The fifth is next longer, reaching the middle 

 of the fourth. The third slightly exceeds the fourth and second, which 

 are about equal to each other. There is much basal webbing between 

 the three intermediate digits — especially between the third and fourth— 

 "which carries their apparent bases far beyond the bases of the lateral 

 digits. 



In its relative length, the tail exceeds that of any other Xorth American 

 •(mammal?) rodent, always greatly exceeding the head and body, and 

 sometimes measuring nearly twice as much. It is cylindrical, with uni- 

 form taper and very slight caliber, coming to a tine point with a slight 

 pencil of hairs. Its hairiness is about on a par with that of Mus muscn- 

 Jus, decumanus, &c. ; that is to say, insufficient to hide the verticillate 

 whorls of scales between which the short hairs spring. 



The general pelage of this animal is coarse and hispid, with little 

 gloss, and presenting a streaky or "staring'" appearance, owing to the 

 number of bristly hairs which are mixed with the softer under fur. The 

 color varies a good deal in different specimens, though one i)attern is 

 pretty constantly preserved. About one-third of the colored part of the 

 fur — that is to say, a dorsal strip about as wide as the lateral strip on 

 either side — is brownish-yellow, heavily shaded with brownish-black. 

 The sides, with the outer surface of the limbs, are of this same sandy- 

 yellowish, but so slightly lined with the blackish that the purity of the 

 light color is scarcely' interfered with. The under parts are snow-white, 

 with a pretty sharp line of demarcation from the colored areas. The 

 'backs of the hands and feet are whitish. The tail is rather indistinctly 



