Longhurst 1939 Perognathus parvus July 3 E. and Miller's Island 200 ft. Columbia R., Klickitat Co, Wash. Cheek pouches contained seeds of Brome grass. The Perognathus collected on the island appeared to be generally smaller and lighter colored than those of the mainland. July 15 Maryhill, 200 ft., Klickitat Co. Wash. Here Perognathus were found on the higher plateau some distance back from the R. They were observed in cultivated fields in sandy soil. Their mounds were not abundant, however, and as usual were closed at the surface. Burrows are usually filled in showing only a small pile of loose sand on the surface. Where the sand is firmer the burrows are sometimes left open for some distance. Large closely joined mounds indicate that a mouse has dug in the same locality for some time. Johnson and I dug out one burrow and found it about 1 ft. in depth and about 2½ ft long with several side branches all plugged. The mouse was finally discovered at the end of one of the branches apparently completely surrounded by sand.