MAMMALS OF THE MEXICAN BOUNDARY. 



311 



foot, 4:3; head, 50. Skull, 15 b}^ 20. Mamm», i pairs. Pattern 

 striped, as in Tain las and FJutaiitias^ but without a median dorsal 

 stripe. A broad white stripe extends along the side, from shoulder 

 to thigh, narrowing posteriori}^; and this is bordered above and below 

 by black, the lower black stripe being the most pronounced. The 

 rest of the upper side of the body is grizzled vinaceous cinnamon, 

 intimately mixed with l)lack anteriorly, and more vinaceous posteriorly. 

 Ci'own, cheeks, sides of neck, shoulders, and outer aspect of limbs 

 vinaceous cinnamon. Side of head with a whitish line extending from 

 nose to ear, involving the eye; underside of head, white. Sides of 

 body yellowish, paler and grayer next to the black longitudinal stripes. 

 Under surface of body, soiled yellowish white. Tail grayish yellow, 

 sometimes vinaceoias, the lateral hairs thrice ringed with black. Ears 

 coated with short, ferruginous hairs, both surfaces, white at base 

 anteriorly. 



Skull. — The skull (tig. 49) of Callospevmophilus lateralis differs 

 widely from those of Amniospermophilns leiicurus and A. harrislL In 

 fact, the lateralis group stands out distinctly from both the genera 

 Tainias and Eutamias, and from AmmoHjyermophihis, and merits sepa- 

 ration as a section of the genus ClteUus. (Since the above was written 

 it has been named Callospermophilus by Merriam, and regarded as a 

 full genus.) 



The skull closel}^ resembles that of typical Citellus{Mas ciiellus Lin- 

 naeus). The brain case is less flattened superiorly than in Ammosper- 

 mopJdlus., with more prominent and higher parietal crests. The audital 

 bullte are smaller, and the width of the basi-sphenoid, basi-occipital, 

 and interpter3'goid notch relatively much greater. The incisive fora- 

 men is longer. 



Cranial measurements of 4 adult females of Callospermophilus lateral is from near 



Flagstaff, Arizona. 



jRemarks. — The larger ears, and the addition of black longitudinal 

 stripes, are in the direction of the genera Tamias and Exitamias; but 



