Lepidosternons.- 



-KEPTILES.- 



-TlIE ClIIKOTES. 



85 



under ground, feeds upon earth-worms, slugs, insects, 

 &c., and it is said to malie especial war upon ants' nests. 



Family— LEPIDOSTERNID^. 



The second family, that of the Lepidosternons, differ 

 chiefly from the true Amphisbtenas, in having their 

 cliests covered with shields of a larger size and a dift'er- 

 ent shape from those of the rest of the body, and by 

 the body having three lines which divide the rings of 

 scales into three sots. Tliere are only throe species 

 described, all natives of Brazil. 



Family— CHIROTIDiE. 



The third family, that of the Chirotes, differ from 

 the two preceding families by the possession of two 

 legs. These are the front members, and are placed 

 near the head. They are, liowevor, very short and 

 weak, but are furnished with five toes, four of which 

 possess a claw. 



THE MEXICAN CHIROTES {Chirotes lumhricoidcs) 

 — represented in I'late 3, fig. 4 — is the only species 



known. This curious-looking animal is about eight or 

 ten inches long, and is a native of Mexico. The 

 structure of its teeth, and the rings of scales with 

 which its body is covered, connect it with the Amphis- 

 bajuas, otherwise its shape and sliort legs would lead 

 one to place it amongst the lizards, close to the Chal- 

 cides. Tiie scales of the body are nearly square, 

 and, like the true Amphisba:nas, are divided into two 

 sets by a lateral lino on each side. The tail is short, 

 cylindrical, rounded at the extremity, nearly of the 

 same size as the head and body ; and the rings are 

 entire, not divided by the line which runs along the 

 sides of the body, but which terminates at tlie vent. 

 The number of rings upon the body amounts to one 

 hundred and fifty, and those of the tail to about thirty- 

 one. The head of the Cliirotes is rounded in front, 

 and scarcely distinguishable from the body; and the 

 eyes are almost imperceptible, covered with a trans- 

 parent skin, and destitute of eyelids. The feet are 

 only about four or five lines long, and are covered with 

 rings of scales similar to those of the body. Little or 

 nothing is known of its habits. 



Class — AMPHIBIA. — Frogs, Toads, Salamanders, &o. 



The term Amiiliihia, amphibions animals, is derived 

 from the Greek word ampluhios {a.;j,fiii3ioi), which 

 signifies " having a double hfe." The denomination is, 

 in general language, applied very loosely, to mean any 

 animal that is so organized as to resort habitually to, 

 and seek its food in the water as well as on land ; to 

 any animal, in short, such as the walrus, the otter, 

 water rat, &c., whose habits are aquatic as well as ter- 

 restrial. Strictly speaking, however, the term Am- 

 phibious applies only to such animals as Iiavo both 

 internal lungs to fit them for breathing atmospheric 

 air, and gills, such as fishes have, to enable them to 

 breathe in the water. The number of animals so 

 organized, when they have arrived at an adult state, 

 is very small ; but there are many wliich at an early 

 stage of their existence are so organized, and at differ- 

 ent periods of their life possess both lungs and gills. 

 Both of these groups of animals belong to the present 

 class, and the general name of Amphibia has been 

 retained by systematic naturalists for them exclusively. 

 Li those which at an early age are furnished with 

 gills, and like fishes, respire water, those organs in due 

 time become obliterated, and the lungs then develojie. 

 These are the frogs, toads, newts, &c., and are called 

 Citducibranchiale amphibia, or " amphibious animals 

 with perishable gills." In the other group, the gills 

 are permanent organs, remaining after tlie owners have 

 acquired lungs, and thus the animal can live indiffer- 

 ently either in the water, respiring like fishes, or on 

 land, breathing like mammalia. These are the Axo- 

 lotl, Lepidosiren, Proteus, and Siren, and are called 

 Peremiibranchiate amphibia, or "amphibious animals 



with persisting gills." By many naturalists, the Am- 

 X>hibia, instead of forming a class by themselves, con- 

 stitute only an order of the great class. Reptiles. They 

 ditTer, however, so much in many essential characters 

 from all the other orders of that class, that they are 

 fairly entitled to the rank of a distinct class of animals 

 by themselves. Instead of being covered with scales, 

 plates, or shields, the skin is naked, smooth, and often 

 moist, and lubricated with a fluid secretion, and aids 

 the lungs by affording a surface for the aeration of tlie 

 blood. The lungs are equal in size on both sides, and 

 of a cellular structure; and the young are sidyect to a 

 metamorphosis. The body of amphibious animals is 

 either depressed, and squat, as the toad, &e.; elongated, 

 like the salamanders and newts, &c.; or rounded, as 

 the ca;cilias. Tlie head is depressed and joined to the 

 body without any distinct neck or division. They 

 have all a distinct and well-developed sternum, but the 

 ribs are either only rudimentary or are altogether 

 wanting. The vertebroe or bones of the spine, in the 

 back, are variable and not easily distinguishable from 

 each other — in the tailless species, as the frog, being 

 only ten, and in the sirens, being ninety in number. 

 In many of the species the body is destitute of a tail ; 

 while in the otiieis, this organ is well developed. The 

 limbs vary in form and number; in some being well 

 developed, in others being very incomplete, and in 

 several altogether wanting. The toes are destitute of 

 nails or claws, or, at the most, are only provided with 

 small horny sheaths. They are in general, Iiowever, 

 well adapted for receiving the impressions of touch. 

 The sensorial fimctions are blunt. Though the nervcs 



