134 CALIFORNIA MAMMALS. 



Family Geomyidae (The Pocket-Gophers.) 



Body stout, thickset; head wide and blunt; eyes and ears 

 small ; mouth peculiar in having no lips, the large incisors pro- 

 jecting through the ordinary skin, which is haired behind them, 

 the real mouth opening just in front of the premolars; dieek 

 pouches large and opening externally, these pouches being purse- 

 shaped infoldings of the loose skin of the neck, lined with short 

 hairs, reaching back nearly to the shoulders and held in place by 

 small muscles; legs very short and strong; feet large, with five 

 toes each ; claws of fore feet very large ; tail about half as long 

 as the head and body, scantily haired, the tip endowed with tactile 

 nerves; skuU large; lower jaw massive, strongly curved; incisors 

 very long and stout ; squamosal much expanded ; mastoids re- 

 stricted to the occiput. 



This family contains nine genera and more than one hundred 

 nominal species and subspecies; a considerable number of these 

 will probably be dropped when the genus is critically studied as a 

 whole. The distribution is temperate North America, exclusive 

 of the Middle and New England States, Mexico and Central 

 America. Most of the genera and many of the species are Mexi- 

 can. But one genus is known to occur in the United States 

 west of the Rocky Mountains. 



The food is mostly vegetable, a large part consisting of 

 roots and tubers. Succulent plants are drawn into the burrows 

 and eaten. It is probable that such worms and insects as are 

 incidentally found are also eaten. That part of the food obtained 

 beneath the surface is found by the laborious process of digging 

 burrows through the soil. Openings to the surface are made 

 every few feet for the purpose of disposing of the soil excavated. 

 If food plants chance to stand quite near to these openings they 

 are cut and drawn into the burrow. If seen at a little distance 

 from the burrow the animal prefers tunneling to them, rather 

 than venture a few feet on the surface, so reluctant is the animal 

 to expose itself by leaving its burrow. They are cautious but 



