B. Richardson 134. 2 3 Microtus californicus californicus were found in the burrow system of apathy system. The nest of this small rodent was composed of dry grass finely shredded and at the entrance the nest was placed green grass evidently food for fly parent. The nest had a diameter of about 5 inches and there were numerous tunnels about the nest but only one being used. The former ones mentioned were certainly young being able to walk only with difficulty and numerous squeaks. Their eyes as yet had not opened. The later two were somewhat older their eyes were open and they were able to shift rapidly about this burrow being almost entirely independent of parental aid. For a more detailed sketch see 25m B. Richardson report on Microtus