Leo Arnold 1937 Thomomys Quadratus Horse Canyon, 5,800 ft., Tehrum T.R., Washoe Co., Nevada. May 29 I caught 2 ♀ T.q. in a small open space just south of camp. The spot was surrounded with rose bushes and there was short "bunch glass growing here and there on the ground. The soil was fine, moist end dark but was full of small rocks. These ranged from the size of a pea to that of a walnut. This seemed to make digging difficult—consequently the holes were very small. May 30 Caught 2 more near the same spot as that of the 29th—one ♀ and one ♂. These two were larger than the first. One feature of the habitat was the fact that the burrows were located in a place where constant seepage kept the soil very moist at this time of the year. "Snowplugs" from the preceding winter could be seen here and there.