DESCRIPTIONS OF TWO SUPPOSED NEW SPECIES OF MICE FROM 

 COSTA RICA AND MEXICO, WITH REMARKS ON HESPEROMYS 

 MELANOPHRYS OF COUES. 



BY 



J. A. Allen, 

 Curator in the Amei-ican Aluseiim of Natural History, Nezv York. 



Having recently had iu hand a small collection of mammals from 

 Costa Eica for identification, I found it desirable to examine iu that 

 connection as much material as possible from Central America and 

 Mexico bearing upon the Costa Eican Muridte. In response to my 

 solicitation, Mr. Frederick W. True, curator of mammals in the U. S. 

 National Museum, kindly secured for me the use of the specimens in 

 the collection under his charge. They not only were of great assist- 

 ance in the work in hand, but proved to include two forms apparently 

 new to science. 



Oryzomys talamancae, sp. nov. 



Pelage short, thick, soft, velvety. Above, russet-brown medially, 

 mixed with blackish brown, passing gradually into clear yellow-brown 

 on the sides ; beneath, grayish white, the hairs being white or faintly 

 yellowish white at the tips and gray beneath the surface, the basal 

 gray portion showing through the surface, giving the etTect of grayish 

 white with a faint yellowish cast. Cheeks, sides of the neck, and flanks 

 deep yellowish brown or golden cinnamon. Sides of the muzzle, dull 

 soiled grayish white. Upper surface of fore and hind feet, dull pale 

 yellowish gray, very scantily haired, and the toes nearly naked, except 

 at the base of the claws. Soles entirely naked, tubercles G. Bars large, 

 blackish, naked. Tail about as long as head and body, naked, black- 

 ish above, dark brown below, hence indistinctly bicolored. 



Length (approximate from skins), head and body, 114.3 millimetres 

 (4.50 inches) ; tail, 114.3 millimetres (4.50 inches); hind foot (with claws), 

 30.8 millimetres (1.15 inches); ear, from crown, 13.7 millimetres (.54 

 inch); muzzle to eye, 17.8 millimetres (.70 inch). 



Skull in general form very similar to that of Orysomi/s palustris^ but 

 much smaller. Basal length, 28.5 millimetres ^1. 12 inches); total length, 

 31.2 millimetres (1.23 inches) ; palatal length, IG millimoters (.G3 inch) ; 

 greatest breadth, 15.8 millimetres (.63 inch) ; least interorbital breadth, 



Proceedings National Museum, Vol. XIV— No. 850. 



Proc. N. M. 91 13 193 



