106 SCIURUS. 



D. Arseosciurus, 



Premolars, j^j. Skull broad, depressed between orbits; superior 

 outline curved greatly at occipital region; orbital region very broad; 

 postorbital process curving downward, and pointed; nasals long, 

 extending posteriorly to end of premaxillae. 



FIG. 16. SCIURUS IAR/EOSCIURUSI NAYARITENSIS. 



No. 4741 Field Columbian Mus. Coll. Nat. size. 



KEY TO THE SPECIES AND SUBSPECIES OF THE SUBGENUS. 



A. Size large. Premolars, |^. PAGE 



a. Back with longitudinal black band 5. oculatus 107 



b. Back without longitudinal black band, 

 a/ Under parts white. 



a." Above gray, washed with blackish; tail 



beneath yellowish gray or brown 5. o. toluca 107 



b." Above grizzled yellowish brown; tail 



beneath grizzled yellowish gray 5. alleni 108 



