176 Bulletin American Museum of Natural History. [Vol. XXXIV, 
about 46% of total length. Pelage thick and soft; coloration about as in 
the hoffmanni group of Mesoscrurus. Mamme, 6. . 
Skull narrow, rostrum very long and narrow; nasals 103% of interorbital 
ey. Fig. 18. Fig. 19. 
Figs. 17-19. Syntheosciurus brochus Bangs. Type skull, nat. size. 
breadth, 29% of total length of skull, their posterior border deeply emargi- 
nate; zygomatic breadth about 48% of skull length. 
Premolars, #; incisors grooved in front; p® well developed; molariform 
dentition not specialized. 
Known only from a single species, from Chiriqui, Panama, where it lives 
at an altitude of 7000 feet. 
Syntheosciurus is surprisingly unlike any other known squirrel, having 
no very close relationship with its near neighbors, Microsciurus and Meso- 
sciurus, which occur in the same region, and of course is very different from 
the large Echinosciuri of the same general area. 
Genus Parasciurus. 
Plate IV, Figs. 4-6; Plate V, Figs. 1-9: Plate VI, Figs. 17-24. 
Parasciurus Trouessart, 1880 (subgenus of Sciurus). Type, Sciurus 
niger Linné, by monotypy. 
Areosciurus Nelson, 1889. Type, Sciurus oculatus Peters, by original 
designation. 
Size large, among the largest of American tree squirrels; tail long and 
broad, about 50% of the total len gth. Pelage thick and soft; color of upper- 
parts gray (generally dark gray with fulvous suffusion), underparts white or 
buffy, sometimes ferruginous. Mamme, 8. 
Skull broad and heavy, dorsal outline flattened over the frontal region, 
