It is extremely common on all the islands throughout the group, and lives exclusively on the rocky sea-beaches, being never found, at least I never saw one, even ten yards inshore. It is a hideous looking creature, of a dirty black color, stupid and sluggish in its movements. The usual length of a full grown one is about a yard, but there are some even four feet in length; a large one weighed twenty pounds. The tails are flattened sideways, and all four feet are partially webbed. They are occasionally seen some hundred yards from the shore swimming about. When in the water this lizard swims with perfect ease and quickness, by a serpentine movement of the body and flattened tail—the legs being motionless and closely collapsed to the sides. A seaman on board sank one, with a heavy weight attached to it, thinking thus to kill it directly; but when an hour afterward he drew up the line it was quite active. Their limbs and strong claws are admirably adapted for crawling over the rugged and fissured masses of lava, which everywhere forms the coast. The nature of this lizard’s food (seaweed) as well as the structure of the tail and feet, and the fact of its having been seen voluntarily swimming out at sea, absolutely proves its aquatic habits; yet there is in this respect one strange anomaly, namely, that when frightened it will not leave the island. Hence it is easy to drive these lizards down to any little point overhanging the sea, where they will sooner allow a person to catch hold of their tails than jump into the water. They do not seem to have any notion of biting; but when much frightened they squirt a drop of fluid from each nostril. I threw one several times as far as I could into a deep pool left by the retreating tide, but it invariably returned by a direct line to the spot where I stood. It swam near the bottom, with a very graceful and rapid movement, and occasionally aided itself over the uneven ground with its feet. As soon as it arrived near the edge, but still being under water, it tried to conceal itself under the tufts of seaweed, or it entered some crevice. I several times caught the same lizard by driving it to a point, and, though possessed of such perfect powers of diving and swimming, nothing could induce it to enter the water; and as often as I threw it in it returned in the manner described above. Perhaps this singular piece of apparent stupidity may be accounted for by the circumstance that this reptile has no enemies whatever on shore, whereas at sea it must often fall a prey to the numerous sharks.