MARMOSA. 5 
Micoureus Less., Tabl. Régn. Anim., 1842, p. 186. 
Asagis and Notagogus Glog., Handb. Naturg., 1, 1841, p. 82. 
Thylamys (sic) Gray, List Mamm. Brit. Mus., 1843, p. ror. 
Grymeomys Burm., Thiere Bras., 1, 1854, p. 135. 
Cuica Liais, Climats, Géol., Faun. et Geog. Botanique, Breésil, 
1672, pe 427. 
Size small; pouch absent; fifth hind toe sometimes not longer 
than the second; tail long; body slender; teeth large, strong. 
KEY TO: THE SPECIES: 
A. Size small; face without dark central streak. 
a. Under parts yellowish white. PAGE 
ay pen patie TUlOUS: sae bo. key du wo murine 5 
Pere per sOnrhs aGimmlammOn 5.2 <1. ted he M. mexicana 6 
c.’ Upper parts ashy brown; skull, 35 x 20...M. canescens 6 
de’ Upper parts brown; skull, 31x 76.5...... M. sinaloe 6 
Seaemerapminor ray. sgl bys os ou ho wei ead M. cinerea 7 
b. Under parts buffy yellow or buff. 
emi @et. pamus ca OLOWM. « . 0's 5r.ie-s see eft M. insularis 7 
bY’ Upper parts dark sepia brown............JM. oaxace 8 
c.’ Upper parts cinnamon or tawny ochraceous.......... 
sis Ao nO eG OA « At og M. fulviventer 8 
2. murina (Didelphis!), Linn., Syst. Nat., 1, 1758, p. 55. 
Murine Opossum. TJlacuazin Raton in Guatemala. 
Type locality. Unknown. (‘In Asia; America.’’) Brazil?’ 
Geogr. Distr. Central Mexico to Brazil. 
Genl. Char. Tail furry at base; ear large, rounded, naked, basal 
projection long, pointed. Skull: nasals long, of nearly equal width 
throughout their length; supraorbital ridges present, tips forming 
postorbital processes; temporal ridges not meeting in center of brain- 
case. 
Color. General hue above deep rufous, sides paler; cheeks, throat, 
chin, and lips buff; orbital ring and space between eyes and nose 
black; under parts and inner side of limbs yellowish white or buffy; 
outside of limbs like back; hands and feet flesh color; tail covered 
with rufous hair at base, remainder pale brown. 
Measurements. Total length, 395; tail vertebre, 218; hind foot, 
26; ear, 29. Skull: basal length, 33; length of nasals, 15; across 
postorbital processes, 7.2; palatal length, 20; length of upper molar 
series, 6.4. 
