130 IjaiKjo — IKtix Field Muti^i: Ji'otti, SciijuandhduL 



De-'icrlptioii. 



TijtH. — No. 1104 (^ ad. Coll. of E. A. and O. Bangs, Boston, Mass. 

 From Codi'oy, Newfoundland, Nov. 27, 1893, P>nest Doane, collector. 

 Total length, 187 mm.; tail, 54 mm.; hind foot, 24 mm.; ear, 12 mm. 

 (These measurements taken in flesh by the collector.) 



Above: Brown, of a color between raw umber and Front's brown, becom- 

 ing gradually lighter on the sides, with a slight sprinkling of shining black- 

 tipped hairs oh the back. 



Under parts : Grey No. 9,* with an indistinct line of darkei' (about the 

 color of the sides) runnmg up the middle of ihe belly nearly to the front 

 legs. 



There is a well defined nose-patch extending from the nose to and around 

 the roots of the whiskers, of a dull tawny color. The base of the hair is 

 everj-where blackish slate. The tail is distinctly bicolored — above, black ; 

 below, grey No. 10,* and quite hairy. 



Cranial and dental characters: The skull of Arvicola ten\Tnov;r is broad and 

 short, and has the flaring zygoma and great interorbital coiistiiction of A. 

 xanthognatkus. The rostral part is also narrow as iu that species. The 

 pattern of enamel folding is, on the other hand, more like that of ^1. 

 riparius, with the difference that the last loop of the posterior upper niolar 

 is trifoliate, as against the creseut shape of riparius There are one or two 

 other trifling differences in the enamel folding that can be better seen by a 

 critical examination of the accompanying drawing."!' 



This Arvicola seems to occupy au intermediate j)Osition be- 

 t\veen the xa nthofpiathus and ri/pariiis groups. The indication of 

 nose-patches can occasionally be found in individuals of A. rip- 

 arius, but I never have seen a series from any one place that 

 shovi^s any tendency to this marking, while every one of my series 

 of sixty-three A. terrfcnovx. has a distinct, though dark colored 

 and not conspicuous nose-patch. 



The rather peculiar marking of the under parts is constant 

 through the entire series ; indeed, I have seldom seen a series of 

 mammals more uniform in every respect. 



Mr. Doane found this field mouse common everwhere about 

 Codroy, where he spent the winter, and where all my specimens 

 came from. 



*Rirlgway's Nomenclature of colors, Plate II. 



fExcellent figures of the skulls t>f A. riparius, A. xanthognathus, and A. 

 chrotorrliinus can be found in " On a Collection of Small Mammals from the 

 New Hampshire Mountains, by Gerrit S. Miller, Jr.", in the Proceedings of 

 the Boston Society of Natui-al History, Vol. XXXVI, Plate 3. 



