170 PEROMYSCUS. 



cinnamon coat bordered with white beneath. The majority, how- 

 ever, are modestly dressed in the hue for which their familiar family 

 name has provided an appellation mouse color, varied with shades 

 of black, russet, and numerous tints of yellows and browns, with 

 white harmoniously applied and blended. Usually the under parts 

 are white, as are the hands and feet also; but again these latter are 

 often plumbeous in different shades. They are the gleaners of our 

 fields and woods, often graceful of shape and always agile of foot, the 

 "small deer" of our land. 



No careful revision of Peromyscus has as yet been made, and 

 until that is done, the status of many of the forms now deemed 

 distinct and the arrangement of the species cannot be satisfactorily 

 determined. 



4:2. Peromyscus. Field Mice, Deer Mice. 



Peromyscus Gloger, Handb. und Hilfsb. Naturg., 1841, p. 95. Type 

 Peromyscus arbor eus Gloger =Mus sylvaticus noveboracensis 

 Fischer. 



Calomys Aud., Quad. N. Amer., n, 1851, p. 303. (nee Waterh., 

 P. Z. S., 1837, p. 21.) 



Vesperimus Coues, Proc. Acad. Nat. Scien. Phil., 1874, p. 178. 



Baiomys True, Proc. U. S. Nat. Mus., 1894, xvi, p. 758. 



Trinodontomys Rhoads, Proc. Acad. Nat. Scien. Phil., 1894, p. 257. 



Haplomylomys Osgood, Proc. Biol. Soc. Wash., xvn, 1904, p. 53. 



Size moderate, eyes rather prominent; face rather long, nose 

 pointed; ears thin, rather rounded, in some species very large. Feet 

 small, digits slender, palms naked; hind feet long, soles with six 

 tubercles; tail terete, tapering, slender, hairy, sometimes longer than 

 head and body, and occasionally tufted; pelage soft, frequently glossy. 

 Skull thin, papery; braincase broad, rather flat, superior outline 

 curving both ways from highest point just behind orbits ; zygomata 

 slender, threadlike, dipping midway to level of the palate, zygomatic 

 arch composed mainly of processes of the maxillary and squamosal. 

 Orbital foramina just above the level of the alveolus; interorbital 

 constriction considerable, but wider than rostrum; nasals and inter- 

 maxillae project beyond the incisors; auditory bullae small, thin, and 

 obliquely situated; lower jaw straight; coronoid very short; molar 

 series short, narrow, the teeth decreasing in size from front to rear; 

 upper molars with three roots each, the lower with two, and the un- 

 worn teeth have a double series of conical tubercles, which gradually 

 are reduced by abrasion, and the pattern varies constantly. 



