The two larger species, representing both the spiny and the silky groups, were much more bold and quickly became confiding and delightfully friendly. Their attention was promptly attracted to rolled oats which I scattered on the ground in a spot well lighted by the candle. Sitting quietly close by the bait where the visitors congregated I soon had evidence that among themselves these little beasts are extremely pugnacious. The first to reach the food would fiercely charge the next comer and always try to leap upon its back, at the same time delivering a vicious downward kick with its strong hind feet. Occasionally the newcomer would charge the one already at the food. When five or six were trying to secure sole possession of the small food pile there was lively skirmishing about the premises, as they alternately attacked and pursued one another over the sand and among the boxes and other camp gear scattered about. Amazingly quick in movements, they would leap now forward, now sidewise, now straight up a foot or more in the air, with almost equal celerity; and the direction of their movements when attacked was often unexpected. When running about on the level sand they had a steady, swiftly gliding motion, which their tracks showed was the result of a series of little jumps. Both the spiny and the silky pocket mice became so confiding the first night that when I put my hand on the ground palm up with a little rolled oats in it the nearest pocket mouse would run to it, stop for an instant to smell the finger-tips, and then mount and sit quietly on the palm and fill its cheek pouches. At such times the mice showed no uneasiness, even when raised in my hand to within a few inches of my eyes in order that I might observe their movements more closely. The motions of their front feet when putting food into the pouches were so rapid that it was impossible to follow them. The nose was held just over the food pile, and the cheek pouches would slowly but visibly swell as they were filled until they stood out like little bladders on each side of the head. As soon as they were full the mice became uneasy to get away and would run from one side of my hand to the other peering down the abysmal depth of three feet to the ground without daring to leap. As soon as my hand was lowered to the ground the mouse darted away to carry the food to its store in the bushes twenty to thirty yards away, quickly to return with empty pouches.