VOL. XI, PP. 43-44 MARCH 16, 1897 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



DESCRIPTIONS OF TWO NEW MURINE OPOSSUMS 

 FROM MEXICO. 



BY C. HART MERRIAM. 



Two very different types of pigmy opossums are known from 

 Mexico the 'red' or rufous Marmosa murina (Linn.) and the 

 pale ashy gray M. canescens (Allen). Mr. Nelson obtained rep 

 resentatives of M. murina at Chicharras and Huehuetan, Chiapas, 

 and Juquila, Oaxaca, and of M. canescens at Santo Domingo de 

 Guzman, Isthmus of Tehuantepec (the type locality); Puerto 

 Angel, Tlapancingo, and Oaxaca, Oaxaca; Amolac, Puebla; 

 Tlapa, Lochi, and Acapulco, Guerrero, and Hacienda Magda- 

 lena, Colima. 



The specimens of the M. murina type are paler rufous than 

 the typical form and have the middle of the face abruptly lighter, 

 so that it is necessary to recognize them as a geographic race or 

 subspecies. The Oaxaca specimens of the canescens type are 

 markedly darker than typical canescens and differ in other re 

 spects. The form is here described as distinct under the name 

 M. oaxacte. 



Marmosa oaxacae sp. nov. 



Type from City of Oaxaca, Oaxaca, Mexico. No. 68240, 9 adult, U. S. 

 National Museum, Biological Survey collection. Collected August 14, 

 1894, by E. W. Nelson and E. A. Goldman. Original No. 6571. 



Geographic distribution. Sonoran fauna of highlands of Oaxaca; limits 

 of range unknown. 



General characters. Size small, smaller than a half-grown rat; similar 

 to M. canescens (Allen), but very much darker, and with the dark of upper 

 parts reaching wrists and ankles; feet and ears smaller. 



8 Bior, Soc. WASH., Voi,. XI, 1897 (43) 



