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 premaxille to palatal 
arch, 17; length of mandible, 22; height at condyle, 3; at coronoid 
process, 7. 
Fic. Il. MARMOSA CINEREA. GRAY OPOSSUM. 
No. 7052 Field Columbian Mus. Coll. 
5. cinerea (Didelphis!), 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., x11, 1898, p. 14. 
Maria MapRE Is_tanp Opossum. 
Type locality. Maria Madre Island, State of Jalisco, Mexico. 
