'.)'2C) BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Heaird and inrdsiiri'iii.niis of SI KjieciinenK of OlnxjiiTiiKj/ihilnx lirrrhi:;/! — Cnntiiuit'il. 



Locality. 



San Isidro Ranch, Lower Cali- 

 fornia. 



do 



do 



do '. 



do 



do 



Edge of Pacific Ocean, at Mon- 

 ument No. 258. 



Date. 



1894. 

 June 28 



June 29 

 ....do... 

 ....do... 

 June 30 

 July 2 

 July 13 



Sex and 

 ago. 



y ad. 



5f ad. 

 (Tad. 

 ?ad. 

 cfad. 

 cTad. 

 cTad. 



mm. 

 400 



440 

 403 

 396 

 418 

 403 

 420 



mm. 

 167 



179 

 163 

 150 

 168 

 173 

 182' 



trrni. 

 54 



56 

 55 

 63 

 56 

 54 

 66 





mm. 

 19 



22 

 21 

 20 

 21 

 20 

 21 



Genus CITELLUS Oken (1816). 



Citellm Oken, Lehrbuch der zoologie, II, 1816, p. 842.— Allen, Bull. Am. Mus. 

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



Type. — Mvfi citelhis Linnseus. 



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

 to slender and weasel-like. Tail variable. Cheek-pouches alwaj'^s 

 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 Oynomys, 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 ICTIDOMTS Allen. 



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

 and flattened, or 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. Iridecem. lineatus, 

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



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

 n. s., II, p. 418, September 27, 1885.) 



