REPTILES. 



the left, hut both kinds of blood are partially mixed in passing 



iliruu.-li the ventricle: their body is inveloped by two plhtes, or 



r>, formed by the ribs anil sternum, supported by four 



li* envelop* of the body permits no part to project, ex- 

 rept the head, neck, tail, and four feet. The upper shield, 

 which is called the r.ir/iurr, is formed by the rib-,, of which 

 there are riirht pairs, these are widened and reunited by den- 

 ti, uluted suturei., and with plates adhering to the annular 

 portion of the dorsal vertebra, in such a manner, that all 

 the** parts are deprived of mobility. The lower shell, called 

 V>r platlron, is formed of pieces, usually nine or ten in num- 

 ber, analogous to a tterniiin ; and this has been denominated 

 ti.e ttemum by the more recent writers on natural history. 

 A frame work, consisting of bony pieces, which have been 



, 



analogous with the cartilaginous portion of the 

 ribs In the mammalm, generally encompasses the upper shell, 

 uniting all the ribs which comprise it. The vertebrae of the 

 Deck and tail are alone movcitble. 



These two bony envelopes being covered with skin or by 

 scale*, the scapula and all the muscles of the arms and neck, 

 Instead of brink' articulated to the ribs and spine, tut in other 

 animal*, are attached beneath ; the same arrangement is found 

 in the bones of the pelvis, and also in all the muscles of the 

 tliifh, so that in this respect tortoises have been termed re- 

 t inverted animals. The vertebral extremity of the scapula is 

 articulated with the shield, and the opposite extremity of the 

 clavicle with the breastplate or sternum, in such a manner, 

 that the shoulders form a ring for the passage of the trachea 

 nnd oesophagus. A third aud larger bony branch, is directed 

 downward and backwards, representing the coracoid apohysis 

 iu birds. 



The lungs are extensive, and situated in the same cavity 

 with the other viscera. The thorax being immoveable in the 

 greater number, it is by the action of the mouth that the tor- 

 toise respires ; this process being effected by keeping the jaws 

 closed, aud alternately raising and depressing the oshyoides. 

 The first movement permits the' air to enter by the nostrils, 

 and the tongue afterwards closing the interior opening, the 

 second movement forces the air into the lungs. 



Tortoises are devoid of teeth ; their jaws are invested by a 

 horny covering, similar to the mandibles of birds, except in 

 the Chelides, where they are covered with a skin only. 

 Their tympanum and palatine arch are fixed to the cranium 

 and immoveable ; the tongue is short and bristled with fleshy 

 filaments ; their stomach simple and strong ; their intestines 

 of medium length, and destitute of a caecum. 



Tortoises lay numerous eggs, which are invested by a hard 

 shell. These are deposited in the warm sand, under the in- 

 fluence of a southern sun, where they are abandoned by the 

 parents, and are batched in summer by the influence of the 

 atmosphere. 



The animals of this order possess great tenacity of life, and 

 they have been known to move for several weeks after am- 

 putation of the head. They require but little nourishment 

 and can pass whole months, and even years, without food. 



II. THE SAURIA, or Lizards, have a heart with two auri- 

 cles, and a ventricle sometimes divided by imperfect partitions 

 and their body covered by scales, supported by four or two feet. 

 The ribsare moveable, and partially attached to the sternum, 

 and can be raised or depressed during respiration. The lung 

 extends more or less towards the posterior part of the body ; 

 it frequently penetrates very far into the lower part of the 

 abdomen, the transverse muscles of which, pass under the 

 ribs, and even towards the neck to clasp it. Those species 

 in which this organ is very large, possess the singular faculty 

 of changing the colours of their skin, according to the excite- 

 ment produced on them, by their wants or passions. 



Their mouth is invariably provided with teeth, and in most 

 instances, their toes are armed with nails ; their skiu is 

 covered with scales, more or less compact, and in a few spe- 

 cie* with scaly granules. All the species have a tail more or 

 less long, which is very thick at th base. Most of them have 

 uiiir legs, but a few have only two. They subsist on animal 

 food. Like the animals of the former order, they deposit 

 their eggs favourably to their being- hatched, where they 

 abandon them ; the young animal is hatched perfect in its 

 form, and never undergoes any metamorphosis. 



III. THE OPBIDIA, or Serpents, have a heart with two 

 auricles, and are destitute of feet, consequently they are the 

 only order of this cla-s, to which the name reptile is strictly 

 applicable. 



Cuvier divides this order into three families. In the first, 

 the terms Anguinet, the toeth and tongue of which are simi- 

 lar to those of the genus Seps, of the preceding order, and the 

 eye in provided with three eyelids. The second family, or 

 the true serpents, all the genera are destitute of a sternum or 

 slightest development of collar bones; the ribs are 

 Articulated to each other by a convex and a concave surface, 

 and encompass almost the entire circumference of the-trunk. 

 They arc devoid of the third eyelid and tympanum. Although 

 their head* are large, the true cranium forms but a small 

 portion of it. Their eyes are fixed, but they are destitute of 

 external ears. Their nostrils are short, and but slightly 

 developed, and are generally situate at the extremity or sides 

 of the muzzle. The tongue varies much with the species ; 

 and although it I* soft, moikt, long, and forked, it seems rather 

 MtetdtO assi-t in h.-izing their prey, than a- an onran of 

 taato. The fcaly covering with which they are invested, 

 necessarily renders their sense of touch rather obtuse. They 

 change their skin at least once a year. The third family 

 eir. braces the Naked serpents, or those remarkable animals 

 which form the genus Cacilia. 



The whole (inimnls of this order are provided with conical 

 and curved teeth, which seem rather fitted for securing their 

 prey, than for gnawing their food. Some of the genera are 

 lurnished with pervious fangs in the superior jaw, which, when 

 erected, press a gland or SRC, in which is a deadly poison, 

 which flows through the tube, and is injected into the wounds 

 pierced by the fangs. In many species, the jaws are united 

 in the middle, which renders the mouth susceptible of consi- 

 derable dilatation, and enables them to swallow their prey 

 entire. The process of digestion is extremely slow in all the 

 animals of the order ; and after feeding, they assume a lethar- 

 gic condition, in which they continue frequently for weeks. 



Serpents possess a heart with two auricles and one ventri- 

 c'e, divided into two compartments, and they have only a 

 sinirle lung. Their circulation is slow. The only sound 

 emitted by serpents is a hissing noise. The eggs are usually 

 protected by a covering, or shell, which is somewhat calcare- 

 ous ; when laid, they are commonly united like a string- of 

 beads, or in the form of a wreath. Some species are, however, 

 viviparous. 



IV. THE BATRACHIA, are provided with a heart which has 

 but one auricle, and a single ventricle ; their body is naked ; 

 most of the species are metamorphosed from the form of a 



g. 

 e heart is branched into as many steins as there are gills. 



reptile. 



All the Batrachian reptiles are destitute of scales, shields, or 

 nails on their toes ; the whole body and limbs being covered 

 only by a naked skin. Their eggs have a membranous 

 covering. In some species fecundation is performed during 

 the extrusion of the eggs ; in others they are deposited in 

 some favourable situation, and afterwards impregnated in the 

 same manner as the spawn of fishes. 



ORDER I. CHELONIA. 



Heart provided with two auricles ; body inveloped in two 

 bony plates or shields, which are formed from the ribs and 

 sternum ; furnished with four feet. 



SUBDIVISION I. LAND TORTOISES, 



Testudo. Upper shell gibbous, begirt with a bony frame, 

 and united nearly a!l round the sides to the lower shell ; feet 

 furnished with short obtuse toes, united almost to the nails ; 

 these, as well as the head, can be withdrawn within the shell; 

 fore feet with five nails, hinder feet with four. 



Testudo radiata, the Radiated Tortoise. PI. 78, fig. 1 . 

 Shell black, ovate smooth ; provided with flattened scutella, 

 having yellow radiations ; upwards of twelve inches long. In- 

 habits Madagascar. 



SUBDIVISION II. FRESHWATER TORTOISES. 



Emys Europaea, European Eiuys. Superior shell gibbous, 

 divided into compartments by large scales; feet provided 

 with distinct, more or less palmated, toes, five before and 

 four behind, armed with crooked nails. 



Emys picta, the Painted Tortoise, pi. 78, fig. 2. Shell ob- 

 long, slightly convex, smooth, brown, each of the scutella 

 bordered with yellow, broadest on the anterior margin ; the 

 disk composed of thirteen, and the margin of twenty-five 

 pieces ; shell six inches long. Inhabits North America. 



Cistuda. Superior plate, emarginate in front, with two 

 notches behind ; sternum with one or two divisions, which 

 are susceptible of motion ; lips corneous. 



Cistuda clausa, the Close Tortoise, pi. 78, fig. 3. Shell 

 brownish black, with irregular yellow spots; ecutella striated, 

 parallel to their sides ; middle yellowish, and the dorsal ones 

 carinated ; anterior part of the under shell moveable ; four 

 or five inches long. Inhabits North America. 



Chelonura Serpentina. Upper shell carinated, with sharp 

 processes behind ; limbs incapable of being- withdrawn within 

 the shells ; tail about the same length as the shield. 



SUBDIVISION III. SEA TORTOISES. 



Chelonia Feet depressed into scaly fins ; provided with 

 unequal toes, which are elonsated, scaly, and united by a 

 membrane, with very small nails upon their exterior border, 

 and terminated by scaly laminae. 



Chelonia imbricata. the Hawk-billed Turtle. PI. 78. f. 4. 

 Shell cordiform, with thirteen imbricated semi transparent 

 variegated scales on the disk ; marginal pieces twenty five ; 

 head small ; neck long ; beak narrow and sharp ; from three 

 to five feet long. Inhabits the seas of the Torrid Zone. 



Chelysfimbricata. Shell not sufficiently large to receive 

 the linibs ; mouth cleft across ; lips fleshy, and nose elongated 

 into a small proboscis j toes webbed. 



