new Mammah from Tropical South America. 517 



Skull of the same long narrow shape as in M. impavida, 

 Tsch., and the supraorbital edges similarly with line narrow 

 btadings parallel to each other, not thickened as in all the 

 previous species, and not projecting laterally over the orbits. 

 Teeth decidedly smaller than in impavida. 



Dimensions of the type (measured in skin) : — 



Head and body 130'mm. ; tail 158; hind foot 18; ear 25. 



ISkull : greatest length 35*4; condylo-basal length 34*2; 

 zygomatic breadth 17-6; nasals 16-8 x 4-3; interorbital 

 breadth G ; breadth of brain-case 12-8; palate length 19-4; 

 three anterior molariform teeth 5'7. 



Hah. N.W. Bolivia. Type from Eio Solocame, G7° W., 

 16° S. Alt. 2300 m. Another specimen from Mapiri. 



Type. Adult female. B.M. no. 1. 6. 7. 79. Original 

 number 1329. Collected 26th January, 1901, by Perry 0. 

 Simons. Presented by Oldfield Thomas. 



Readily distinguishable from its nearest ally, the M. im- 

 pavida of Central Peru, with which it shares the general 

 structure of the skull, by its wholly light belly and smaller 

 teeth. 



Marmosa paraia, sp. n. 



Allied to true J/, mxirina, but teeth not so small. 



More grey-brown than in most of the group of red Mar- 

 mosas, the general colour above similar to, but considerably 

 darker than, " wood-brown/' Under surface " pinkish 

 buff," the hairs of the belly slaty at base nearly or quite to 

 the middle line. Dark orbital patch large, extending nearly 

 to the tip of the nose. Hands and feet brownish white. 

 Tail grey-brown to the tip. 



Skull with broadly expanded zygomata. Interorbital 

 region with angular ledges projecting over the orbits. Teeth 

 larger than in true M. luurina. 



Dimensions of the type (measured in flesh) : — 



Head and body 140 mm.; tail 180 ; hind foot 18; ear 24. 



Skull : greatest length 35'8 : condylo-basal length 34*6 ; 

 zygomatic breadth 20 ; nasals 15'2 x 5"1 ; interorbital breadth 

 6*2 ; breadth across postorbital processes 7'7 ; breadth of 

 brain-case 13*7 ; palatal length 19'7; three anterior molari- 

 form teeth 5"8. 



Hab. Para. Type from Igarape-Assu. Alt. 50 m. 



Type. Adult female. B.M. no. 4. 7. 4. 100. Original 

 number 1879. Collected 12th May, 1904, by A. Robert. 

 Presented by Oldfield Thomas. 



