MURID.E— ARVICOLIISLE— ARVICOLA QUASIATER. 



227 



soles are very sparsely hairy — a central line of nakedness, at least, extending 

 almost to the heel. The plantar callosities are not perfectly plain in the dried 

 skin, but there appear to be only five: one on the inner side of the foot, mid- 

 way between the heel and tip of the inner, toe; one at the base of this toe; 

 one at the base of the second toe; one at the bases of the third and fourth 

 toes ; and one at the base of the outer toe ; none of them are prominent. 

 The hairs on the dorsum of the feet are scanty, the longest barely reaching 

 the tips of the nails. The fore feet, measured from the extreme palmar 

 tubercle, are just half as long as the hinder and rather broader; the nails 

 seem a trifle longer, and certainly are no shorter than those of the hind. 

 The rudimentary thumb and its obtuse abortive nail are as usual in the genus. 

 The ears are large for this section of the genus, and obviously overtop the 

 fur a little ; they are rounded ; in the dried state, the anterior margin of the 

 conch is reflected, but this may be an accident of preparation ; the rest of 

 the auricle is flat ; the antitragus is but slightly developed, being little more 

 than a stiff ridge, incapable of closing the meatus. The flat part of the 

 conch is pretty closely furred both inside and out — the hairs being short and 

 pilous, rising but little beyond the margin of the ear. The tail is very slen- 

 der as well as short, moderately hairy, and with a slight terminal pencil. 



The following measurements are believed to be a very close approxima- 

 tion to the truth, owing to the skillful preparation of the specimens by their 

 distinguished collectors : — 



Dimension. 



Nose to eye 



Nose to ear 



Nose to root of tail 



Tail to end of vertebra .. . 



Tail to end of hairs 



Height of ear in front 



Height of ear behind 



Length of palm 



Length of sole 



Length of fur on the, back 



The type-specimen, No. 3524 (Mus. Smiths.), was taken at Xalapa, Mex- 

 ico, by M. R. M. De Oca. No. 7006, taken at Tuxpango, Mexico, by Prof. F. 

 Sumichrast, does not differ in any appreciable degree. These are the only 

 Mexican Arvicolte we have seen. 



