92 MAMMALS OF PENNSYLVANIA AND NEW JERSEY. 



tion to the Life History of the Allegheny Cave Rat" (1. c.), endeavored to 

 show that the living and so-called " fossil " Neotomtz were specifically the 

 same. In his Review of the Neotomyina (1. c.), Dr. Merriam considers them 

 distinct, but Dr. J. A. Allen, in a recent paper, inclines to the belief that they 

 are identical. Dr. E. A. Mearns and G. S. Miller, Jr., now (Bull. Amer. Mus. 

 N. History, 1898, pp. 334, 335, and Bull. N. York State Mus., 1899, p. 318) 

 agree that the fossil and recent species are distinct, having compared Baird's 

 types with skulls of pennsylvanica. The differences pointed out by Mearns 

 consist in the relatively shorter, stouter mandible and dentition of magister. 

 I have recently examined this scanty material with Mr. Stone, and find that, 

 so far as it goes, Mearns' remarks are germane, though these differences 

 amount to only i millimeter in mandibular length and breadth, the tooth row 

 of magister being of the same length and about a hair's breadth wider. 



The general characters of pennsylvanica resemble, in a degree, those of the 

 common, or Norway rat, Mus norvegicus {decumanus of authors), but dis- 

 tinguished by greater size, much larger ears and eyes, thicker, shorter and 

 much more hairy bicolored tail, white feet and under parts, dark upper parts 

 and the heavy whiskers. The skull is instantly recognized by its great size, 

 long rostrum, lack of supraorbital ridges and the flat, prismatic-crowned 

 molar teeth. The cave rat is distinguished from the southern wood-rat, 

 Neotoma floridana, its nearest geographic ally, by greater size, more hairy 

 and bicolored tail and grayer (less brown) color above ; also by the blackish 

 areas around eyes and at bases of whiskers. The color of pennsylvanica above 

 is a uniform tawny or buffy-gray (in some a sort of iron-gray), lined plenti- 

 fully with coarser and longer black-tipped hairs. Along sides, the buffy pre- 

 dominates, becoming white on under parts and feet, but reaching nearly 

 across the fore part of breast. Ears meeting when laid across top of head. 

 Whiskers reaching to or behind shoulders. Tail with upper half darker than 

 back, lower half white, the hairs long and somewhat depressed along sides. 

 Greatest length of skull twice its greatest breadth. 



Measurements. Total length (average of 5 adults from Somerset and 

 Cambria Cos.), 421 mm. (i6 T 9 ^- in.) ; tail vertebrae, 193 (7!) ; hind foot, 43 

 (IY|) ; ear, from crown of head, 28 ( i). Skull : greatest length, 56 f2 T 3 ^) ; 

 greatest breadth, 28 (i). 



Genus Evotomys Coues, Proceedings Academy Natural Sciences, 

 Phila., 1874, p. 186. 



Gapper's Wood Vole, or Red-back Mouse. Evotomys gappen 

 (Vigors). 



1830. Arvicola gapperi Vigors, Zoological Journal, vol. 5, p. 204. 



1891. E\yotomys~\ gapperi Merriam, North American Fauna, No. 5, p. 119. 



