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220 



MONOGRAPHS OF NOUTH AilEBICAN RODENTIA. 



Diagnosis. — Arvicola staturd inter minimos, {long, trunci 3-i-poll.), formd 

 quasi-talpoidea sed rodro obtuso, caudd brevissima (subpollkari), auriculis parvis 

 rotundatis planis subpilosis vellere occuhis, pedibim exiguis, b-tubftculatis, mani- 

 bus latis dimidium pedum excedentibus, unguibus majusculis; vellere curto, denso, 

 sericco, supra castaneo aut brunneo, sublux canescetUe-plumbeo. 



Little Meadow Mouse, looking something like a mole, with close silky 

 fur brown above and hoary gray below; tail shorter than the head; small 

 hind feet, with only five tubercles; comparatively large fore feet, more 

 than half as long as the hinder, and with longer claws; and small, flat, round, 

 scant-haired ears concealed in the fur. 



Habitat. — United States, chiefly east of the Mississippi, and rather 

 southerly ; north to Massachusetts and Missouri. Kansas {Goss). Fort 

 Cobb (Palmer). Oregon {U. S. Expl. Exped., Peale). 



Some of the expressions in the foregoing diagnosis rather belong to the 

 subgenus Pitymijs than to this particular species. The dentition will be 

 found fully elucidated under head of Pitymys; here we will continue our 

 account of P. pinetorum with a notice of the skull, append a table of meas- 

 urements, and then recur to external features. Nos. ^rr, 9 , and Wi , i , both 

 from Tarborough, N. C, are more selected for description as being the most 

 perfect, but the other twelve specimens arc likewise taken into account. 



Skull. — It gives an impression of being broader and more massive than 

 that of riparius; and figures do bear out the suggestion, although in truth 

 the difference in v 'dth or height, as compared with length, is slight; the 

 length relative to the width is as 92 : 57, or as 1.00 : 0.G2, on an average, 

 whereas the same proportion in riparius is 1.00 : 0.59 only. The absolute size 

 of the skull is as much less as was to have been expected from the animal's 

 smaller stature, and the di""erence appears to be positively distinctive; for we 

 have never seen an (adult) skull o^ riparius that fell below one inch, and never 

 one of pinetorum (hat touched this figure. Still we suspect that some Mas- 

 sacliusetts skulls, for example, might reach it. Our specimens range from 

 0.90 to 0.97 in length, and the zygomatic width is just about I us much. 

 Tiie average width of pinetorum is just at par with the minimum width of 

 riparius. There is a noticeable difference in the interorbital width, however; 

 the constriction here being no greater absolutely than that oi. riparius, and 

 consequently i)eing relatively less. The ante-zygomatic or rostral part of the 

 skull is perhaps broader for its length, as well as absolutely shorter. In the 



