Perhaps this singular piece of apparent stupidity may be accounted for by the circumstance that this reptile has no enemy whatever on shore, whereas at sea it must often fall a prey to the numerous sharks. Hence, probably urged by a fixed and hereditary instinct that the shore is its place of safety, whatever the emergency may be, it there takes refuge. On a comparison of this singular animal with the true iguanas, the most striking and important discrepancy is in the form of the head. Instead of the long pointed narrow muzzle of those species, we have here a short obtusely truncated head, not so long as it is broad; the mouth consequently is capable of being opened to only a very small extent. From this circumstance, and from the crest on its head, it has received the Latin name of _Amblyrhynchus cristatus_.
The serpent race, which thrives so abundantly in the tropical forests and morasses, has also its marine representatives in the Indian and Pacific Oceans, where more than fifty species of Hydrophis, Pelamys, and Chersydra have been found. They are distinguished from their terrestrial relations by the flattened form of their tail, the planes of which being directed vertically give it the properties of a powerful oar, in striking the water by lateral oscillations. These sea-snakes always appear to prefer calms, swimming on the still surface in an undulating manner, never raising the head much from the surface, or vaulting out of the water. They dive with facility on the approach of danger, but do not appear to be particularly timid.
The Pelamys bicolor is very common from India to Otaheite. In the seas of Mindoro and Sooloo, Mr. Adams saw thousands swimming on the top of the water, especially in eddies and tide-ways where the ripple collects numerous fish and medusæ, which principally constitute their prey. Their tongue is white and forked, differing in respect of its colour from the tongue of other snakes, which is generally black. The water-snakes, which are frequently beautifully banded, and as thick as a man's leg, are said to be highly venomous. Captain Cook, in one of his voyages, "saw abundance of water-snakes, one of which was coming up the side of our ship, and our men beat it off. The Spaniards affirm there is no cure for such as are bit by them; and one of our blacks happened to fall under that misfortune, and died notwithstanding the utmost care was taken by our surgeons to recover him."