The Sauria include the Crocodiles, Alligators, Skinks, Geckos, Iguanas, and Lizards; they are carnivorous, the smaller ones feeding on insects, and the larger members on whatever they can catch. They have four legs, and are covered with hard rough scales running in ridges on their backs, they have large strong tails, and their jaws are furnished with sharp teeth. The Alligator is found in great numbers in the Mississippi, and is a most formidable creature, attacking any who may venture into the water. In winter they bury themselves in the mud and remain there in a torpid state, they are from 15 to 20 feet long. The Crocodile is a native of Africa and the West Indies, there are many found in the Nile, it is larger than the Alligator, reaching often to 30 feet. Dr Baird gives the following account of the Alligators and Crocodiles:-- [Illustration: FIG. 49.--1, CROCODILE (Crocodilus vulgaris); 2, ALLIGATOR (Alligator lucius); 3, LIZARDS.] "The Alligator (Alligator lucius, fig. 49), a native of North America and abundant in the Mississippi, is a formidable and ferocious creature, prodigiously strong, and sometimes reaching the length of 18 feet. It is provided with numerous sharp teeth, long tenacious claws, and a powerful tail, a single blow of which is capable of overturning a canoe. It chiefly preys by night, assembling in large numbers, besetting the mouth of some retired creek, into which they have previously driven the fish, and bellowing so loud that they may be heard at the distance of a mile. It is said to attack men and quadrupeds whilst bathing or crossing the rivers, and to be more fierce and voracious then the other species of this sub-family. In Winter it buries itself in the mud at the bottom of the swamps and marshes which it inhabits, and continues in a torpid state till Spring. "The true Crocodiles are natives of Africa, the West Indies, and America; and the best known species is the Nilotic Crocodile (Crocodilus vulgaris, fig. 49). This animal is a native of the Senegal river, of the Niger, and other rivers of Africa, but more particularly of the Nile in Egypt, where it attains the length of about 30 feet. The Crocodile was held in great veneration by the ancient Egyptians, by whom it was known under the name of 'Champsa.' The Crocodiles are exclusively carnivorous, and are ferocious animals. Their numbers are, however, kept down by the enemies which surround them. For the adults, few animals could be their match, but the little Ichneumon or 'Mongooz' devours their eggs in great numbers while hatching in the sand; and birds of prey pounce upon their young on quitting their shell, and before they are able to reach the shore." 4. TESTUDINATA (having a shield).