SAURIA NS, and BATRACIANS.
The CHELONIANS have a short,• thick, oval body, cover ed with a horny shell or membranaceous coat. The tipper or dorsal part of this is called the shield, and is formed of the vertebrae and ribs, cemented together within or beneath the outer covering ; and the lower or 'sternal part is called the breastplate. The head is supported by a pretty long neck, and the mouth is furnished with two mandibles, gene rally, resembling•the bill of a bird. These tribes are in gene ral slow in motion, possess little sensibility, and have a lan guid circulation and slow respiration. They live chiefly on vegetables. They generate by copulation, in which act they remain for several days. Their eggs are covered with a shell, and are deposited by the female in the sand, or among loose earth or gravel. The young are hatched in the form which they are to preserve through life.
The Chelonian order is divided by Dumeril into four ge nera, Chelonia, Emys, Chelys, and Testudo ; but as the third of these comprehends only one species, and the second is distinguished from the fourth only by a few minute differ ences, we shall continue the division of Cuvier into two ge nera, Chelonia and Testudo ; the former compre hendnig the sea tortoises, or turtles, which have the articulated mem bens in the form rather of swimming paws than feet ; and the latter, or the tortoises, having feet more or less digitat ed, and furnished with distinct claws.
The SA URIA Ns, or lizards, have a lengthened scaly body, feet armed with claws ; a tail that is often of considerable length, and the jaws beset with teeth. Their legs are in
general short ; and consequently their pace, though quicker than that of the former order, is slower than that of most quadrupeds ; and as their legs are set wide from the body, their progress is unsteady and oblique. The reptiles of this order also copulate, deposit their eggs to be hatched by chance. The young are extruded in a perfect state.
Of the Saurian order, Daudin reckons sixteen genera, which we shall divide, with Dumeril, into two Sections, Plant caudata, or flat tailed, and Tereticaudata, or round tailed. Of the flat-tailed Saurians we have four genera : Crocoddus, having a flattened head, the scales on the back of unequal size, and the hind feet palmated ; Drac,ena, hav ing a square head, and toes distinct ; Basiliscus, having equal dorsal scales and a crested ridge along the back, sup ported by bony rays ; and Tupinambis, having equal scales but no dorsal ridge. Of the round-tailed section there are twelve genera, viz. Iguana, having a crest on the back, and a serrated crest on the throat ; Draco, having the sides furnished with membranes resembling wings ; 4gan2a, hav ing an oblong scaly body and tail, an inflated throat, and the feet long and thin, each furnished with five slender se parate toes ; &till°, having a spinous tail covered with Ca ri:tated scales ; Chameleo, having feet formed for climbing ; Gecko, having a thick body, and a throat capable of being dilated by inflation ; Andis, having a long thin body, and