Have the head large, covered with a thick skin, ears closed with two valves, gape very wide, tongue short, jaws with a single series of cone-shaped teeth inserted in sockets; back with a hard disc formed of a longitudinal series of square keeled plates of hard bony consistence embedded in the skin; the under surface covered with smooth thin square plates; legs short, feet webbed, with four to five toes, the three inner toes of each foot only armed with claws. They are divided into two groups:-- I. _Crocodilidæ_, having the lower canines fitting into a notch in the edge of the upper jaw. II. _Alligatoridæ_, having the canines fitting into a pit in the upper jaw.] CROCODILES. The Shielded Saurians, as Duméril designates the largest of living species of that order of reptiles, have the body depressed, elongated, and protected on the back with a solid carinated shield or buckler; the tail longer than the trunk, compressed laterally, annulated and crested above; having four very short feet; the toes of the posterior feet united, or web-footed, each foot having three claws only; head depressed and elongated into a muzzle; the gape of the mouth extending back beyond the skull; tongue fleshy, adherent; teeth conical, simple, hollowed at the base or towards the root, unequal in length, and in a single row. Such is a brief summary of the family by Duméril and Bibron. If the Eagle is the king of the air, the Tiger and the Lion the tyrants of the forests, and the Whale the monarch of the deep, the Crocodile has for the exercise of his undisputed control the maritime shores of tropical seas and the borders of tropical rivers. Living on the confines of land and water, this formidable reptile is at all times the scourge of those human beings who are compelled to reside near its haunts. Much larger than the Tiger, Lion, or Eagle, the Crocodile surpasses all terrestrial animals, with the exception of the Elephant, Hippopotamus, and some Serpents, in its power of destruction.