SUPPLEMENTAL NOTE ON REPTILES. 



433 



cept in the Chelids, where they are covered with a skin 

 only. Their tympanum and palatine arch are fixed to 

 the cranium and immovable; 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 influence of a southern sun, where 

 they are abandoned by the parents, and are hatched in 

 summer by the influence of the atmosphere. The ani- 

 mals 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 nourish- 

 ment and can pass whole months, and even years, with- 

 out food. 



II. The Sauria, or Lizards. have a heart with two au- 

 ricles, and a ventricle sometimes divided by imperfect 

 partitions and their body covered by scales, supported 

 by four or two feet. The ribs are movable, and par- 

 tially attached to the sternum, and can be raised or de- 

 pressed 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 excitement 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 skin is covered with scales, more or less com- 

 pact, and in a few species with scaly granules. All the 

 species have a tail more or less long, which is very thick 

 at the base. Most of them have four legs, but a few have 

 only two. They subsist on animal food. Like the ani- 

 mals of the former order, they deposit their eggs favour- 

 ably to their being hatched, where they abandon them ; 

 the young animal is hatched perfect in its form, and 

 never undergoes any metamorphosis. 



III. The Ophidia, or Serpents, have a heart with two 

 auricles, and are destitute of feet, consequently they are 

 the only order of this class, to which the name reptile is 

 strictly applicable. C'uvier divides this order into three 

 families. In the first, the terms Anguines, the teeth and 

 tongue of which are similar to those of the genus Seps, 

 of the preceding order, and the eye is provided with 

 three eyelids. In the second family, or the true serpents, 

 all the genera are destitute of a sternum or the slightest 

 developement 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 are devoid of the third eyelid and tympanum. 

 Although their heads 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 is soft, 

 moist, long, and forked, it seems rather destined to assist 

 in seizing their prey, than as an organ of taste. The scaly 

 covering with which they are invested, necessarily ren- 

 ders their sense of touch rather obtuse. They change 

 their skin at least once a year. The third family em- 

 braces the Naked serpents, or those remarkable animals 

 which form the genus C&cilia. The whole animals 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 furnished 

 with previous fangs in the superior jaw, which, when 

 erected, press a gland or sac, in which is a deadly 



Eoison, which flows through the tube, and is injected 

 ito the wounds pierced by the fangs. In many species, 

 the jaws are united in the middle, which renders the 

 mouth susceptible of considerable dilatation, and en- 

 ables 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 lethargic con- 

 dition, in which they continue frequently for weeks. 

 Serpents possess a heart with two auricles and one ven- 

 tricle, divided into two compartments, and they have 

 only a single 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 calcareous ; when laid, they are commonly 

 VOL. II. 



I 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 fish, breathing by the branchiae, or gills, 

 to that of a quadruped, breathing by lungs, when in a 

 perfect condit ion. In two genera, however, namely, the 

 Serena and Protetis, they retain the gills. In the 

 former condition the aorta leading from the heart is 

 branched into as many stems as there are gills. In 

 those species, the branches which lead to the gills are 

 all obliterated except two, which unite in a dorsal 

 artery, give off each a small branch to the lung. This 

 fact, as observed by Cuvier, is the circulation of a fish, 

 changed into that of a reptile. All the Batrachian rep- 

 tiles 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. 



Testudo radiata,i\\e Radiated Tortoise. PL 25, fig. 1. 



SUBDIVISION II. FRESHWATER TORTOISES. 



Emys Europosa, European Emys. 

 Emys picta, the Painted Tortoise, pi. 25, fig. 2. 

 Cistuda. 



Cistiida dausa, the Close Tortoise, pi. 25 fig. 3. In 

 habits North America. 

 Chelonura Serpentina. 



SUBDIVISION III. SEA TORTOISES. 



Chelonia. 



Chelonia imlricata, the Hawk-billed Turtle. PI. 25, f. 

 4. Inhabits the seas of the Torrid Zone. 

 Chelys fimbricatd. 

 Trionyxferox. 



ORDER II. SAURIA. 



Body elongated, invested with scales, generally fur- 

 nished with four feet ; toes armed with claws, at least 

 in part ; tail more or less long ; mouth generally with 

 numerous teeth. 



FAMILY I. CROCODILIDJS. 



Body elongated, covered with square scales, of which 

 the upper and under are the largest, and those above, 

 raised into a ridge or corina in the middle ; provided 

 with four feet, with five toes before, and five behind, the 

 three interior armed with nails, and all of them more or 

 less united by membranes ; each jaw provided with a 

 single row of acute teeth ; tongue fleshy, depressed, 

 and almost entirely attached to the lower jaw ; t;iil 

 compressed, and provided above with a strongly dentat- 

 ed crest. The whole animals of this family are large, 

 their bodies are covered with square, or oblong scales, 

 of which those above form elevated lines, which are 

 raised into a double crest on the tail. Their heads are 

 long in proportion to the body, and ponderous; their 

 jaws are articulated behind the cranium. Their nostrils 

 form an elongated canal, which has its origin in the 

 throat, and terminates at the point of the muzzle, where 

 it is provided with a semilunar orifice, which it can open 

 or shut at pleasure. Their eyes are furnished with 

 three eyelids ; the exterior ear is very small and can be 

 closed at the will of the animal, by means of two fleshy 

 coverings ; under the throat there are two glands which 

 secrete a musky substance, through small orifices. The 

 crocodiles are the only family of this order which are 

 destitute of clavicles, or collarbones] but their coracoid 

 3i 



