Natural History of the Ground Squirrels of California f.13, 1918

Original caption: drawings from dissections to show relative extent of cheek-pouches in (a) california ground squirrel and (b) belding ground squirrel. One cheek-pouch opens into the mouth cavity on each side; it is lined with membrane continuous with that lining the mouth and is used for carrying food materials such as seeds and bulbs from the forage ground to either the store house or the husking place. It is to be inferred that the california ground squirrel is much more of a seed-gatherer than the belding. The latter, like the oregon ground squirrel, is more of a grass-eater, and also does not garner food to the extent that the "digger" squirrels do. Date: 1918.