Order VI. Rodentla. 



Coues & Allen, Monograph of North Arnerican Rodentia, U. S. 

 Geol. Surv., 1877, xl. 



Fam. I. Scinridae. 



Tail without scales, cylindrical, bushy, hairs long; distinct post- 

 orbital processes: infra-orbital opening small; molars rooted, tuber- 

 cular; first upper premolar small. 



Sub. Fam. I. Sciurinae. 



O. Bangs, A Review of the Squirrels of Eastern North America, 

 Proc. Biol. Soc. Wash., 1896, p. 145. 



E. W. Nelson, Revision of the Squirrels of Mexico and Central 

 America, Proc. Wash. Acad. Scien., 1899, pp. 15-106. 



36. Sciurus. 



I. J=I; p. ?=?; M. ^ = 22. 

 I— i' I— 1' 3—3 



Sciurus. Linn. Syst. Nat., 1758, i, p. 64. Type 5. vulgaris, Linn. 



Guerlinguetus. Gray, Lond. Med. Repository, 1821, p. 304. 



Macroxus. F. Cuv. Diet. Scien. Nat., 1829, lix, p. 474. 



Rheithrosciurus. Gray, Ann. Mag. Nat. Hist., 1867, p. 272. 



Rhinosciurus. Gray, Ann. Mag. Nat. Hist., 1867, p. 275. 



Neosciurus. Trouess. Le Nat., 1880, 11, p. 292. 



Parasciurus. Trouess. Le Nat., 1880, 11, p. 292. 



Echinosciurus. Trouess. Le Nat., 1880, 11, p. 292. 



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



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



Otosciuriis. Nelson, Proc. Wash. Acad. Scien., 1899, p. 28. 



Arceosciurus. Nelson, Proc. Wash. Acad. Scien., 1899, p. 29. 



Baiosciurus. Nelson, Proc. Wash. Acad. Scien., 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; upper premolars one, sometimes 

 two, in the latter case the first is very small; anteorbital fora- 

 men slitlike, placed anteriorly to the zygomatic process of the max- 

 illary. 



