CLH) 



BULLETIN 56, rxiTKH STATES NATIONAL MUSEUM. 



Ha 



d and measurements ol ■■'/ specimens of Otospermophihis beevheyi — Continued. 



Genus C1TELLUS Oken (1816). 



(Melius Oken, Lehrbuch-der zoologie, II, 1816, p. 842. — Allen, Bull. An 

 Xat. Hist., XVI, p. 375, Oct. 11. 1902. 



Mus. 



Type. — Mus citellits Linnaeus. 



Size medium or small. Form varying from stout or squirrel-like 

 to slender and weasel-like. Tail variable. Cheek-pouches always 

 present, and large. Manus with four well-developed toes and a rudi- 

 mentary thumb, of which the claw may be either present or absent. 

 Skull lighter than in ( ynomys, but more strongly built than in Sciurus 

 or Eutamias, and with the post-orbital processes slender and directed 

 backward and downward; plane of the molar turned outward: zygo- 

 matic arches spreading-. Upper premolars two. but the first premolar 

 simply rounded and single rooted, never more than about one-third of 

 the size of the second. Character of the pelage and pattern of colora- 

 tion variable. 



Subgenus ICTID0MYS Allen. 



Mars generally small, sometimes rudimentary; tail long, cylindrical, or narrow 

 and flattened, <>r quite broad, with the hairs one-half to three-fourths the length of 

 the body; skull very long and narrow; first upper premolar usually rather small, 

 and the dentition not heavy. Species. S. tereticaudus, S. mexicanus, S. tridecem linealus, 

 S. franklini. (J. A. Allen.") 



" Monographs of North American Rodentia, 1877, p. 821. (See Merriam, Science, 



n. s., II, p. -IIS, September 27, 1885.) 



