MARMOSA. 7 



Measurements. Total length, 205-242; tail vertebrae, 115-122; 

 hind foot, 16-18; ear, 22-25. Skull: total length, 31; basal length, 

 29; zygomatic width, 16.5; length of nasals, 13.7; across postorbital 

 processes, 6.2; width of braincase, 11.2; tips of premaxillae to palatal 

 arch, 17; length of mandible, 22; height at condyle, 3; at coronoid 

 process, 7. 



FIG. II. MARMOSA CINEREA. GRAY OPOSSUM. 

 No. 7052 Field Columbian Mus. Coll. 



5. cinerea (Didclphis /) , Temm., Monog. Mamm., i, 1827, p. 46. 

 GRAY OPOSSUM. 



Type locality. Brazil. 



Geogr. Distr. Costa Rica to Brazil. 



Genl. Char. Size large; ear large, rounded, naked. Skull strong, 

 with nasals expanded posteriorly; zygomata widely spread; inter- 

 orbital region flat; postorbital processes conical; temporal ridges 

 rather prominent; canines thick, short. 



Color. General hue gray; sides washed with yellow, sometimes 

 with rufous; black band inclosing the eye; under parts yellowish 

 white; arms and legs gray; feet pale brown; tail furred at base, rest 

 naked, scaly, slaty gray grading into yellow or yellowish white at tip; 

 ears naked, flesh color. 



Measurements. Total length, 425; tail, 248; hind foot, 24; ear, 21. 

 Skull: basal length, 41; greatest width, 26; length of nasals, 18.5; 

 across postorbital processes, 10; palatal length, 23.7; length of upper 

 molar series, 7.1. 



6. insularis (Marmosa), Merr.,Proc. Biol. Soc. Wash., xn, 1898, p. 14. 

 MARIA MADRE ISLAND OPOSSUM. 



Type locality. Maria Madre Island, State of Jalisco, Mexico. 



