1936] MAMMALS OF OREGON 253 



parts bright buffy ochraceous; feet, cheeks, chin, and often spots on belly 

 white. 



Measurements. Average of typical males: Total length, 233 mm; tail, 70; 

 foot, 30.5; ear (dry), 6. Females: 188; 60; 28. 



Distribution and habitat. From a wide distribution in Upper 

 Sonoran valleys of northern California these pocket gophers extend 

 up the Klamath Valley west of Lower Klamath Lake and into the 

 Rogue River and Umpqua Valleys in western Oregon, reaching their 

 northern known limit of range at Cottage Grove in the upper Wil- 

 lamette Valley (fig. 56). 



General habits. These pocket gophers burrow extensively in hard 

 clay or volcanic soil, a habit that seems to account for the protruding 

 and white-tipped incisors, the tips showing scratches and wear that 

 have removed the yellow enamel surface and indicate much use as 

 digging tools. The animal's mounds are often composed of lumps 

 of baked clay, and the burrows extend through hard ground as well 

 as in the mellow soil areas in the open valley country. Rarely are 

 they found in the timbered areas. Little mounds mark the lines of 

 underground tunnels, and the animals are rarely seen except as 

 trapped in the burrows. Often they are difficult to catch because 

 they so frequently push a load of clay lumps into the trap and spring 

 it ahead of themselves. 



Breeding habits. Like other members of the bottae group, they 

 have 4 pairs of mammae, and the regular number of young seems to 

 be 4 to 8. 



Food habits. The food of these pocket gophers includes a great 

 number of the roots and plants encountered in their excavations, and 

 in a fertile and well-settled valley country they find native plants 

 scarce and introduced and cultivated plants abundant and often very 

 acceptable food. All of the clovers and alfalfa are eaten, root and 

 branch, with great relish. In a district especially noted for its fine 

 fruit they do considerable damage and have to be destroyed in every 

 possible way. 



THOMOMYS BOTTAE LATICEPS BAIRD 

 HUMBOLDT BAY POCKET GOPHER 



Thwnomys laticeps Baird, Acad. Nat Sci. Phila. Proc. 7 : 335, April 1855. 



Type. Collected at Humboldt Bay, Calif., by W. P. Trowbridge, February 

 21, 1855. 



General characters. Size and general appearance of bottae but colors 

 warmer and brighter brown, less clouded with black tipped hairs ; skull aver- 

 aging slightly wider and nasals especially wider ; incisors less projecting than 

 in leucodon and without white tips. Upper parts rusty ochraceous or almost 

 snuff brown ; lower parts light buffy ochraceous in strong contrast to upper 

 parts; feet and usually half of tail, lips, and chin whitish. Summer and 

 winter colors the same. 



Measurements. Average of five adult males from type locality : Total length, 

 264 mm; tail, 88; foot, 33. 



Distribution and habitat. Transition Zone coast section of north- 

 western California from Eel Kiver north to the Oregon line. In 

 the year 1927 Jewett took some specimens on the Oregon side of 

 the line near Chetco on the coast, adding this second subspecies of 

 the bottae group to the Oregon list (fig. 56). 



