ORYZOMYS. MELANOMYS. 61 



feet reddish brown; tail above and beneath dark brown, uniform, 

 naked. Ex type in American Museum of Natural History. 



Measurements. Total length, 300; tail, 180; hind foot, 40. 

 Skull:. Total length, 36; Hensel, 28.3; zygomatic width, 20; inter- 

 temporal width, 7; length of nasals, 14; length of upper molar series, 

 5.3; mastoid width, 13; length of mandible, 15.4; length of lower 

 molar series, 5.3. Ex type in American Museum of Natural History. 



Oryzomys richardsoni Allen. 



Oryzomys richardsoni Allen, Bull. Am. Mus. Nat. Hist., XXVIII, 

 1910, p. 99. 



Type locality. Pena Blanca, Nicaragua. 



Color. Upperparts warm buff ; hairs tipped with black, base of 

 hairs plumbeous; flanks light buff, hairs black-tipped; underparts 

 white with a pinkish tinge; top of head like back; sides of head and 

 neck like flanks; outer side of limbs slightly darker than flanks; 

 hands buffy; feet covered sparsely with fine white hairs; tail above 

 pale brown, lighter beneath; ears dark brown. Ex type in American 

 Museum of Natural History. 



Measurements. Total length, 270; tail, 150; hind foot, 32.5. 

 Skull: Total length, 31; Hensel, 24.9; zygomatic width, 17; inter- 

 temporal width, 5 ; length of nasals, 1 2 ; length of upper molar series, 

 4.7; length of mandible, 15.9; length of lower molar series, 5.2. Ex 

 type in American Museum of Natural History. 



Genus Melanomys. 



Melanomys Thomas, Ann. and Mag. Nat. Hist., 7th ser., X, 1902, 

 p. 248. Type Oryzomys phceopus Thomas. 



Melanomys was originally proposed by Thomas as a subgenus of 

 Oryzomys to embrace an aberrant group included by Bangs in the 

 genus Zygodontomys, but differing from the species in that genus by 

 wide skulls, especially between the orbits, and well-marked supra- 

 orbital ridges, a dark colored pelage, almost naked feet and hands, 

 and white nails. Dr. J. A. Allen, has reviewed the group (Bull. 

 Am. Mus. Nat. Hist., XXXII, 1913, p. 533) and raised Thomas' 

 subgenus to full generic rank, recognizing nine species and five sub- 

 species, ranging from the highlands of Nicaragua to northern Bolivia., 

 and eastward to Bogota and the region of the Sierra Nevada de Santa 

 Marta. In Central America two species have been recognized as 

 Zygodontomys chrysomelas and Z. idoneus which must hereafter be 

 included in the genus Melanomys. The first is among the species 



