94 SCIURUS. 



Parasciurus Treuss., Le Nat., n, 1880, p. 292. 

 Echinosciurus Treuss., Le Nat., n. 1880, p. 292. 

 7 ' amiasciurus Treuss., Le Nat., n, 1880, p. 292. 

 Microsciurus Allen, Bull. Am. Mus. Nat. Hist., 1895, p. 332. 

 Hesperosciurus, Nelson, Proc. Wash. Acad. Scien., i, 1899, p. 27. 

 Otosciurus, Nelson, Proc. Wash. Acad. Scien., i, ^899, p. 28. 

 Ar&osciurus Nelson, Proc. Wash. Acad. Scien., i, 1899, p. 29. 

 Baiosciurus Nelson, Proc. Wash. Acad. Scien., i, 1899, p.. 31. 



Tail broad long, bushy, hairs mostly directed laterally; ears 

 moderate, hairy, sometimes with long tufts at tip; no cheek pouches. 

 Skull rather short, broad; postorbital processes directed downward 

 and backward and well developed; one upper premolar, sometimes 

 two; in the latter case the first is always very small; antorbital 

 foramen slit -like, placed anteriorly to the zygomatic process of the 

 maxillary. 



KEY TO THE SPECIES AND SUBSPECIES. 



*A. Size small, total length under 450 mm., but above 300 mm. PAGE 



a. Premolars |^; ears medium long, thinly haired. 



a/ Tail washed with bright f errugineous . . .S.ce. hoffmanni 104 



b.' Tail washed with tawny S. ce. chiriquensis 104 



c/ Tail washed with yellowish S. richmondi 105 



b. Premolars ^E|; 



a/ Ears small or medium, not tufted. 



a." Ears short, rounded, thickly haired; 

 total length under 300 mm. 



a/" Tail washed with reddish S. alfari 99 



b.'" Tail washed with grayish white 5. browni 100 



c.'" Tail washed with tawny olive ... .5. boquetensis 100 

 b/ 7 Ears medium long, pointed, thinly 

 haired; total length over 300 mm. 



a/" Back grayish brown .5. negligens 102 



b/" Back reddish or yellowish brown 5. deppii 101 



c/" Back rusty reddish S. d vivax 102 



c. Premolafs ~ or j^jj. 

 a.' Ears large, tufted. 



a." Back gray, belly white, lateral line 



black S. d. mearnsi 133 



*The construction of an intelligible key for the endless variations displayed 

 by the members of the genus Sciurus is an almost insuperable task, and may 

 not be attempted unless specimens of all the species are available at one time. 

 This not having been possible for the author to accomplish, the present key for 

 the species, with some few additions, has been taken from E. W. Nelson's 

 " Revision of the Squirrels of Mexico and Central America." 



