SCIURIDiE— TAMIAS IIAERISI. 811 



lighter anteriorly and more vinaceous posteriorly, with a narrow white line on 

 each side extending from the shoulder to the hip. Ring surrounding the eye 

 and lower parts pale yellowish-white, varying to clear white. Sides of the 

 body below the white line, especially on the limbs externally, washed with 

 a pale shade of chestnut. Tail flat; above, black, varied and edged with 

 white ; lower surface white centrally and at the edges, with a subterminal bar 

 of black. The hairs of the sides of the tail and some of those of the upper 

 surface are black at the extreme base as well as subtermiually. Ears small, 

 pointed, clothed with short hairs. Soles partly naked in summer, well clothed 

 in winter. The winter pelage (especially at the northward) is full, soft, and 

 silky ; that of the back mostly white beneath the surface. In summer, par- 

 ticularly in Cape Saint Lucas specimens, the pelage is very short, stiff*, and 

 harsh. 



In this species, the variations in color are very slight. The light mark- 

 ings range from nearly pure white to soiled yellowish-white ; the sides vary 

 slightly in the amount of chestnut they present, and the prevailing tint of the 

 dorsal surface varies from gray to pale vinaceous. The hairs are black at the 

 base; those of the dorsal surface, in winter, are mainly white below the sur- 

 face, with narrow basal and subterminal bars of black and yellowish-gray 

 tips. In summer specimens, the pelage is very short and stiff, with no under 

 fur; in winter, long, very soft, with an abundance of silky under fur. 



The present species differs from the other members of the group mainly 

 in having much smaller ears, a shorter tail than either T. asiaticus or T. stri- 

 atum, and in wholly lacking the black dorsal stripes present in all the others. 

 The absence of these, as well as its short ears, serves at once to distinguish 

 it among its congeners. It is, in the average, rather smaller than T. striatus, 

 but rather exceeds in size the smaller varieties of T. asiaticus. It also dif- 

 fers somewhat in habits and in the form of the angle of the lower jaw. It 

 might, in fact, perhaps stand as the type of a new subgenus, coming nearer 

 to Tamias than to Spermophilus. Its chief points of difference from the typ- 

 ical Ground Squirrels consist in its smaller ears and in the very much greater 

 development of the angle of the mandibular ramus, which gives rise to a 

 more strongly marked ascending square process at the posterior upper border 

 Tamias harrisi was first described by Audubon and Bachman in 1854, 

 from a single specimen obtained by Mr. J. K. Townsend on his journey to 

 Oregon, but the precise locality was unknown. Its habitat was first accu- 



