44 On a neto Species of Marmosa. 



Skull : basal length 27'5 ; orbito-nasal length 31 ; 

 greatest breadth 17-5 ; nasals 13-6 X 3-8 ; interorbital breadth 

 5*2; palate length from gnathion 16*5; palate breadth 9'6. 

 Combined length of 7))s.^~^ 5'5. 



J/ab. Ocabamba, Cuzco. 



Type B.M. no. 98. 11. 6. 18. Collected by Herr Otto 

 Garlei)p, October 2, 1897. 



This species may be readily distinguished from its allies 

 by its marked cranial characters and its white-tipped tail, a 

 peculiarity found in the M. cinerea group, but not in any of 

 the smaller members of the genus. 



IV. — On a neio Species of Marmosa. 

 By Oldfield Thomas. 



In working out Herr Otto Garlepp's two species of Marmosa 

 the following proves also to need description : — 



Marmosa pha^a, sp. n. 



A Marmosa allied to M. cinerea^ but very mucli smaller. 



Size about two thirds that of M. cinerea. Fur soft and 

 woolly, about 11 millim. long on the back. General colour 

 above buffy greyish brown, browner than in the grey 

 M. cinerea ; sides with a tinge of isabelline. Middle line of 

 face greyish white. Orbital markings black, not sharply 

 defined, extending forwards without interruption to the roots 

 of the whiskers. Checks, chin, and chest dull buffy yellowish, 

 much duller than in M. rapposa; belly buffy yellow, not 

 sharply defined, the hairs slaty basally. Ears with a basal 

 projection. Limbs coloured externally like back, internally 

 like belly. Carpus, metacarpus, and tarsus brown; fingers, 

 metatarsals, and toes whitish. Tail furry like the body for 

 its proximal three quarters of an inch, then finely scaled, 

 naked, brown basally, white terminally, the two colours 

 mottled at their junction. 



Skull with but very slightly developed supraorbital ridges 

 and processes, less than in any other member of this group. 

 Nasals well broadened, the ])ortion behind the broadening 

 longer than usual. Brain-case smooth and rounded, the 

 temporal ridges scarcely perceptible. Middle and posterior 

 premolars subequal. 



Dimensions of the type (an adult female in skin) : — 



Head and body (c.) 132 millim. j tail (c.) 179; hind foot 

 s. u. (wet) 21 ; ear (wet) 20. 



