Ears of ground squirrels of California f. 01, 1918

Ears of ground squirrels to show characters of size and shape in different species, a, california ground squirrel (spermophilus beecheyi beecheyi); b, fisher ground squirrel (spermophilus beecheyi fisheri); c, oregon ground squirrel (spermophilus beldingi oregonus); d, stephens soft-haired ground squirrel (spermophilus mollis stephensi); e, mohave ground squirrel (spermophilus mohavensis);, yuma round-tailed ground squirrel (spermophilus tereticaudus tereticaudus); g, sierra golden-mantled ground squirrel (callospermophilus lateralis chrysodeirus); h, desert antelope ground squirrel (ammospermophilus leucurus leucurus). All natural size and drawn direct from specimens. Note: a and b are extreme examples; the average difference existing between the california and the fisher ground squirrels is much less; individuals of each race can be found which will overlap some individuals of the other in size and shape. Date: 1918.