272 REPTILIA. 



head and feet, which are particularly large ; their nose is prolonged into a little trunk ; but the mos* 

 strongly marked of their characters consists in having their widely-cleft mouth not armed with a 

 horny beak, as in other Testudinata, but rather resembling that of certain Batrachians, which form 

 the genus Pipa. 



The Matamata (T. fimbria, Gm.).— The carapace bristled with pyramidal eminences, and the body fringed all 

 round with laminae, as if cut. An inhabitant of Guiana. 



The Soft Tortoises {Trionyx, Geoff.) — 

 Have no scales, but merely a soft skin enveloping both the carapace and plastron, neither of which 

 is completely supported by bone, the ribs not reaching to the borders of the carapace, nor being 

 united together for more than a portion of their length, the parts analogous to sternal ribs being 

 replaced by a simple cartilage, and the sternal pieces being partly dentelated, as in the Turtles, and 

 not covering the whole inferior surface. After death it is perceptible, through the dry skin, that the 

 surface of the ribs is very jagged. The feet, as in the Emydes, are palmated without being lengthened, 

 but only three of their toes are provided with nails. The horn of their beak is invested with fleshy 

 lips outside, and their nose is prolonged into a small trunk. The tail is short, and the orifice of the 

 anus beneath its extremity. They inhabit fresh water, and the flexible borders of their envelope 

 assist them in swimming. 



The Trionyx of the Nile (T. triini/juis, Forsk and Gm. ; T. ceyyptiacus, Geoff.) is sometimes three feet long, and 

 of a green colour spotted with white ; the carapace but slightly convex. It devours the young Crocodiles as soon 

 as they are excluded, and thus renders more service to the Egyptians than even the Mangouste. 



The American Trionyx (T.ferox, Gm.) inhabits the rivers of Carolina, Georgia, Florida, and Guiana ; and lies 

 in ambuscade at the roots of the weeds, seizing on birds, reptiles, &c, and devouring the young Alligators, 

 while itself becomes the prey of the larger ones. Its flesh is good eating. There are several more. 



THE SECOND ORDER OF REPTILES,— 



SAURIA,— 



Have the heart composed, as in the Chelonia, of tvvo auricles, and a ventricle sometimes 

 divided by imperfect partitions. 



Their ribs are moveable, attached partly to the sternum, and can rise and fall for the 

 purpose of respiration. 



Their lung extends more or less towards the hinder part of the body, often penetrates con- 

 siderably forward below, and the transverse muscles of the abdomen slide under the ribs ::o 

 far as to entwine the neck. Those in which the lungs are most developed exercise the singular 

 faculty of changing the colours of their skin, according as they are influenced by their wants 

 or by their passions. 



Their eggs have an envelope more or less indurated ; and the young issue from them with 

 the form which they retain ever afterwards. 



The mouth is always armed with teeth ; their toes, with very few exceptions, are furnished 

 with nails ; the skin is covered with scales more or less serrated, or at least with little scaly 

 granules; and they engender with either a single or double male organ, according to the genus. 



All have a tail more or less lengthened, and in nearly every instance very thick at the base : 

 the greater number have four limbs, though some have only two. 



Linnaeus arranged them into only two genera, the Dragons and the Lizards ; but the latter 

 requires to be divided into several, which differ in the number of feet, of intromittent organs, 

 m the form of the tongue, of the tail, and of the scales, so that we are obliged to separate 

 them even into families. 



The first of these, or that of the Crocodiles, comprises but one genus, — 



The Crocodiles (Crocodilus, Brongniart), — 

 Animals of large size, which have the tail flattened at its sides, five toes on the fore-limbs, and four on 



