ABOUT June 20, 1930, an adult female San Diego alligator lizard (Gerrhonotus scincicauda webbii) was collected alive and placed in a glass-fronted cage for observation. At 8 o'clock on the morning of July 17, fifteen eggs were found in the cage. An attempt to incubate some of these failed. The principal food offered the captive was meal worms and it ate as many as eight or ten of these in rapid succession. Beetles, grasshoppers, flies, butterflies and a large sphinx moth were also readily taken. One grasshopper over three inches long was quickly attacked, but was not entirely consumed until the big jumping legs had become detached. On August 2, two very young western fence lizards (Sceloporus occidentalis biseriatus), measuring not over 1Y2 inches from tip of nose to tip of tail, were secured. One of these was dropped into the cage near the alligator lizard and the latter at once grabbed it by the head, crushing it so severely that blood spurted from it. With a few deliberate gulps the prey was swallowed-the tail wriggling vigorously as it disappeared. The second was then placed in the cage several inches from the larger lizard, which at once began to stalk it. The young one made no attempt to flee and in a few seconds it, too, was captured, crushed and swallowed. On several previous occasions I have noticed that small lizards placed in a cage with this large species have disappeared, but have never before actually witnessed lizard feeding upon lizard. On August 5, an egg of the domestic pigeon was placed in the cage with the alligator lizard which tried repeatedly to get hold of it with its mouth, but without success. The egg was rolled all around the cage. An opening was made in the side of the egg, but the lizard failed to take advantage of it. On August 6, a full grown male Pacific tree-frog (Hyla regilla) was placed in the cage with the lizard and was at once seized. After shifting its hold a few times, the lizard dropped its prey and wiped its mouth on the floor of its cage and evinced other signs of having a disagreeable taste in its mouth. The tree-frog remained quiet for a short time and then began to hop about. The lizard once more stalked it but, as the lizard prepared to strike, the tree-frog raised itself on its toes and puffed itself up. It may have emitted some protective vapor, as the lizard withdrew and showed unmistakable signs of discomfiture. A third time the lizard advanced to the attack, but was once more warded off by the frog puffing up and making itself offensive. After this, the lizard frequently looked at the amphibian but made no further attempts to molest it. For several days in the middle of August, a silvery footless lizard (Anniella pulchra), was kept in the cage with the alligator lizard, but was not eaten. The larger lizard several times approached the smaller one in a