MAMMALS OF THE MEXICAN BOUNDARY. 



297 



Rcrard aiul iiivn^iirvnifiilx of 22 xixchiicus (if EutamUts incnianiL 



n Head and body, 130 mm. '< Mammge, 4 pairs. '■ American Museum of Natural History. 

 Genus AMMOSPERMOPHILUS Merriam (1898)." 



Atiimosi)ci'i)i()i)tiihi.'< Me?.riam, Proc. Biol. Soo. Washington. VII. p. 27, 

 April 13, 1893. 



Type. — Tamias leucKrus Merriam. 



Characters.— Dorsum, with one longitudinal stripe on each side; 

 external ears considerably more developed than in Citellus citeUus 

 (Linnaeus), but less so than in CallosperTnophilus; mamnmj, 5 pairs; 

 tail, cylindrical at base, flattened and bushy on terminal tAvo-thirds; 

 skull similar to that of Eu tamias^ but higher and more flattened 

 posteriorly, Avitli relatively shorter and thicker rostrum, narrower 

 palate, heavier dentition, and larger audital bulla^. The skull dif- 

 fers even more from CiteUus in being relatively narrower, flattened 

 above and elev ited posteriorly, with audital biilhv high and com- 

 pressed laterally, and in having the first premolar a much smaller, 

 simple, peg-like tooth. 



a The generic name SpermopMlus, so long in general use for the ground-squir- 

 rels or Speriiiopliiles. lias given place to the older name CitrUiis. and three of 

 its subgenera have been raised to the ranlc of genera. 



