As might be guessed from their powerful hind legs, kangaroo rats travel in bounds. Near Wallula, where we watched them in their natural habitat, they traveled, when unfrightened, in slow hops, each hop followed by a pause. As they struck the surface of the ground an audible thud could be heard for a distance of several feet. After each jump they paused for a second or so, perhaps to allow a pursuing enemy to over-run them. Near Wallula the burrows of kangaroo rats were dug in large mounds of wind-blown sand. The burrows entered these natural mounds horizontally and branched two or three times. Their average length was about five feet. No nests or food stores were discovered although several kangaroo rats were caught as they burst from entrances at sides of the mounds. All entrances to burrows were plugged with soft sand. The air in the burrows seemed warm and humid. Food found in the cheek pouches of kangaroo rats from Washington included the seeds of desert annuals, short sections of sprouts of an unidentified plant, grass seeds, and the leaves of the hop-sage. A female taken March 22, 1939, contained 3 embryos. =Thomomys talpoides= (Richardson) Northern pocket gopher _Description._--The pocket gopher is a fossorial animal, being but slightly less adapted to an underground existence than the moles. The body is stout, the legs short and the head broad. The tail is short, sparsely haired, cylindrical and blunt-ended. The fur is soft and dense. The eyes are small and the ears tiny and naked. The incisor teeth are external, being separated from the mouth cavity by a furry strip of skin. Like the pocket mouse and kangaroo rat, the pocket gopher possesses external, fur-lined cheek pouches. The openings of these begin just below and posterior to the nostrils, sweep out and down in a semicircle, and end at the chin posterior to the base of the lower incisors. They extend laterally to the shoulders and easily accommodate a fifty-cent piece. [Illustration: FIG. 95. Northern pocket gopher (_Thomomys talpoides yelmensis_), from two miles southwest of Tenino, Washington, January 28, 1941. (Fish and Wildlife Service photo by Victor B. Scheffer, No. 1133.)] The family Geomyidae is composed of eight genera, so similar in appearance that the name "pocket gopher" is applied to all of them. The family is confined to North and Central America. Three genera occur in the United States but only one, _Thomomys_, occurs in Washington. _Thomomys_ is restricted to western North America where it ranges from central Canada south to the southern edge of the table land of Mexico. Several hundred kinds of _Thomomys_ have been described and as systematic work with this genus has been continued, more and more kinds, originally thought to be species, are found to intergrade and to be only subspecies. All of the 17 kinds of pocket gophers occurring in Washington belong to a single species.