Their tails are flattened sideways, and all four feet partially webbed.

They are occasionally seen some hundred yards from the shore, swimming about; and Captain Collnett, in his Voyage says, "They go to sea in herds a-fishing, and sun themselves on the rocks; and may be called alligators in miniature." It must not, however, be supposed that they live on fish.

When in the water this lizard swims with perfect ease and quickness, by a serpentine movement of its body and flattened tail--the legs being motionless and closely collapsed on its sides.

A seaman on board sank one, with a heavy weight attached to it, thinking thus to kill it directly; but when, an hour afterwards, 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 form the coast.