ORYZOMYS. 233 



eastern and southeastern portions ; but in Mexico some are met with 

 at 10,000 feet elevation, and these forms are provided with a woolly 

 covering to protect them from the cold of such high altitudes. 



48. Oryzomys. Rice Rats. 



C. H. Merriam. Synopsis of the Rice Rats (Genus Oryzomys) of the 

 L'nitcd States and Mexico, Proc. Wash. Acad. Scien., in, 1901, p. 273. 

 Oryzomys Baird, N. Am. Mamm., 1857, p. 458. Type Mus palus- 



tris Harlan. 

 Oligoryzomys Bangs, Proc. N. Eng. Zool. Club, i, 1900, p. 94, pi. 



i, fig. 2. 



"Form rat -like; ears nearly buried in the fur; hairs of body 

 coarse; tail longer than head and body; the hairs longest on the 



FIG. 39. ORYZOMYS COSTARICENSIS. 



No. 7963 Am Mus. Nat. Hist. Coll. Twice nat. size. 



UPPER TOOTH ROW. LOWER TOOTH ROW. 



Enlarged 10 times Enlarged 10 times. 



