

CHKI.oM.v 



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Muscular .\< n. We have wen tht the shoulder-blade is inter- 

 nal in the tortoises, that is, it is placed on the inside of the ril* ; the 

 muscle*, consequently, of the head and neck, instead of being attached 

 upon the rib* and spine, an in the other Veritbrata, are attached 

 beneath them ; the same observation hold* as to the bones of the 

 lclvis and the muscles of the thigh ; so that, to use Cuvier's expression, 

 a tortoise mar be termed, in this respect, " un animal retourixS " an 

 animal turned inside out, or rather, so to speak, outside in. 



The progressive motions to be accomplished by the bony and mus- 

 cular apparatus of the tortoises are those of walking and swimming 

 or paddling. 



The walk of a tortoise is proverbially slow, such as might be 

 expected from a reptile whose limbs are so imperfectly developed. 

 Short, and placed at a great distance from the centre, they form a 

 sort of short crutches, calculated to drag the unwieldy body gradually 

 along, and if the animal be turned on its back it becomes almost 

 helpless. The feet are little better than stumps, the toes being only 

 indicated externally by what may be termed a collection of hoofs, 

 placed, as in the elephants, on the circumference of the apology for n 

 foot, and which nerve, so to speak, as a sort of grapplings to !>!. I <.-. 

 the surface of the ground and drag the armed trunk onwards, \\ V 

 hardly need add that progression in a vertical direction is impossible ; 

 but many tortoises can burrow with some difficulty. 



Nor is this slowness out of place : the preservation of the animal 

 is provided for by the very strong bony carapace and plastron pro 

 touting the whole body, and only suffering the head, tail, and four 

 feet to be protruded from its anterior and posterior part and it* four 

 angles ; these protruded parts can be withdrawn into the shell upon 

 the approach of danger, and the animal then rests secure in its portable 

 arched castle, leaving the enemy to the hopeless task of besieging a 

 garrison that can remain for months without food. A large Land- 

 Tortoise can defy the whole animal world except man, from whom 

 nothing is safe. 



The most complete defence is made by the Box-Tortoises ; for in 

 them the pieces which form the sternum are moveable, and may be 

 compared to doors or hinged lid*, which shut upon the carapace and 

 thus form a sort of closed coffer in which the head, neck, tail, and 

 feet, in short, the only exposed parts, can at will be inclosed far more 

 securely than a snail in its shell. 



But this slowness is confined to the Terrestrial Tortoises ; for the 

 aquatic species swim with great facility on or below the surface ; and 

 some, CAetoiK and Sphargu for instance, with rapidity. But the well- 

 developed flipper that enables the Marine Tortoise to oar its way with 

 swiftness, is even a worse organ for- land progression than the clumsy 

 foot of a Land-Tortoise. Not but that they will shuffle back to the 

 sea, which they have only occasion to leave in order to deposit their 

 eggs, at a good pace, and they will deal heavy blows with their flippers 

 to those who attempt to stop them (for they, as wall as the Land- 

 Tortoises, are very strong), as those who have been foiled in turning 

 turtles, have known to their colt. 



But however powerfully the muscles which act upon the head, tail, 

 and extremities are developed in this order of reptiles, those of the 

 abdomen, as might indeed be expected, have little extent, and those 

 of the ribs, as might also be divined, are non-existent ; for nature does 

 nothing in vain : but the square muscle of the loius, whose principal 

 office in mammals is to move the lumbar vertebra;, acts in the tor- 

 toises, which have those vertebrae fixed, in another direction, and is 

 employed in drawing up the moveable os ilii ; and the straight muscle 

 (rectus abdominis) which extends from the pubis to the sternum, 

 moves the whole haunch in the greater part of the Tatudinata. 



Digestive System. The Ckclonia have no teeth, although there are 

 often a median groove and denticulated projections and hollows ; but 

 the mandibles are covered with a horny case, as in the birds. The 

 Ckdydt* and the Trionyca, though they have the horny covering. 

 have the mouth furnished with soft skin so as to form a kind of lips. 

 The muscles that work the lower jaw, which is the only moveable 

 one, are very powerful in many of the species ; and the force with 

 which the great Turtles and many other Cheloniana grasp a solid 

 body in their vice of a mouth is prodigious. The Chelydet are the 

 only TrMlmlinatti which have the jaws flat and the gape of the mouth 

 rery wide. 



The food with which the t'lirlunia have to deal is various, and 

 there are modifications in the digestive organs accordingly. The 

 Ckdoitt* and T-t'iullnr, generally prefer a vegetable diet. The Tri- 

 onytt* and C'Mydti prey upon fishes and small aquatic birds ; and the 

 Emydrt attack the weaker animals, such as Crustaceans, Insects, 

 Worms, and Mollusk*. 



These aliment* are submitted in the Terrestrial Tortoise* and in 

 the Chelonians to the trenchant horny lull, w.-ll titled to nm. 

 vegetable fibre, assisted by the tongue, which draws the food into the 

 niinith and tint horny grooves and hollows of the jaws ; the T, 

 and Kmytli, f , i/,- their living prey in their sharp-edged beaks and tear 

 it to pieces with the cutting and pointed claws of their fore feet : 

 some of these dart out their head and long neck upon their prey from 

 an ambush ; or, stealing along like the cats till they come within 

 reach, suddenly extend their destructive apparatus with unerring aim. 

 Mfitif whose fleshy jaws are flat, swallow their prey whole, 

 and in this respect, as well ai in the general conformation of the head 



ninl the OH hyoides, they resemble the Toads, and especially the Tipas, 

 like whirh they are obliged to be content with u vi.-tim of small 

 dimensions suited to the calibre of their mouth, whii-h is, in truth, 

 sutticiently large. They are said never to seize their pn-y till they 

 are satisfied by it* motions that it is alive, for they never food on 

 .-i 



The tongue of the tortoises is fleshy, like that of the parrots, and 

 its nervous papilla; are very distinct. The oesophagus is short, and in 

 the Chelonians is furnished internally with a number of close-set car- 

 tilaginous points, directed so as to prevent the regurgitation i.f the 

 food towards the stomach, which has a transverse position. The 

 intestines are long; the cloaca is situated beneath the tail, and 

 rounded, and internally is found the orifice of canals which terminate 

 in the cavity of the peritoneum. The liver is voluminous, forming 

 two masses or lobes placed transversely below the heart and in front 

 of the junction of the oesophagus with the stomach. The pancreas is 

 a very large gland, and the spleen is rounded, median, and situated 

 at a considerable distance from the liver. The chyle is trnnslucid 

 and aqueous in the vegetable feeders, but of a white and milky tint in 

 those species which feed on animals. 



The power of abstinence in this order of Iteptiles is very great 

 Messrs. Dumcnl and Bibron state that they have seen a Long-Necked 

 Emys remain more than a year without food ; and Redi kept Land- 

 Tortoises fasting for eighteen months. 



Circulating System. The heart in the Chthnia is composed of 

 two auricles, and one ventricle with two unequal chamber* whieh 

 communicate together. The Mood of the body enterx into the rinht 

 auricle and that of the lung into the left; Imt Inith these muditieu- 

 tions of blood mingle more or less in passing by the vontr 



Respiratory System. Cuvier remarks that the quantity of respira- 

 tion in Reptiles is not fixed, like that of Mammals and I'.irds, hut 

 varies with the proportion of the diameter of the pulmonary artery 

 compared with that of the aorta. Thus, he observes, the Tortoises 

 and the Lizards respire much more than the Frogs. 



The lungs are of great extent, and placed in the same cavity with 

 the abdominal viscera. We have seen that the thorax is immoveable, 

 in the greater number at least, and the inlaid fixed ribs can give no 

 assistance in respiration in the full-grown normal forms. It is there- 

 fore by the play of the ports about the mouth that the Chelonia 

 respire, and here the complicated os hyoidea is called into prominent 

 action.- The jaws are closed, and the animal alternately elevates and 

 depresses the os hyoides ; the first movement lets the air enter by 

 the nostrils, and the tongue then closing their interior aperture, the 

 second movement compels the air to penetrate into the lungs. In 

 short, the Tortoises swallow or gulp down the air necessary for their 

 respiration like Frogs. 



John Hunter, in his ' MS. Catalogue,' observes that the vessels of 

 the lungs of those animals whose whole blood passes through them 

 are confined to the lungs, and lungs only, as distinctly as if the lungs 

 were a separate animal; but this, he adds, is not the case with the 

 Amphibia, " for," says he, " we find the vessels of the lungs of the 

 Turtle communicate with those of other parts, such as the vessels of 

 the oesophagus, which shows that the blood of that part is not so 

 perfect in them as in others. From this it must appe:ir that tin- lung* 

 are not of that consequence in this class of animals that they arc in 

 the more perfect, for t lie lungs themselves appear to share in common 

 with the other parts. Some of the blood which just come from the 

 lungs returns bock again to them, which would appear to answer no 



purpose ; and on the other hand a considerable quantity of the 1>! I 



which had undergone the general cireulat ion (aiid therefore would appear 

 to require refinement) just returns through the name course. It would 

 appear from this admixture that it was not necessary that the whole 

 of the blood should have undergone a thorough change for its greatest 

 motion; yet we do not nee why the lunes should have a part of tin ir 

 blood of the perfect kind. The cells of the lung* of the Ami>liiliin 

 seem to increase in i/.e, the farther from the trunk or trachea, so that 

 the trachea and its ramifications bear no proportion between them and 

 the ivi 



i. Nervous System, and Senses. In the Chdonia generally, tin' 

 ! heightof the capiieity of the cranium is greater than in the 

 othfi- Ucptihw; but ill the Sea-Tortoises, or Turtles, the mass of the 

 .u. phalondoes not entirely fill it, and the highly vaulted bones are 

 rather destined to serve as solid point,* of resistance to the upper 

 beak, and to the powerful action of the muscles which act upon >h.' 

 lower jaw. The mass of the encephalon is less elongated and m..i . 

 compact than in the serpents. Bojunus, in his work on the ' Anatomy 

 of the European Emys,' has shown that the great sympathetic or 

 ganglionic series of nerves exists in that reptile nearly as it do. - in 

 the other Yerttbratn ; that on the one hand it has sympath. tic rela- 

 tions with the encephalic and vertebral nerves, and that on the other 

 it makes a communication between the two lateral and synnn. 

 parts of the body, at the same time that its filaments are distributed 

 mid int'-rniingie in numerous plexuses round the principal arteries 

 destined to the nutrition of the internal viscera. Elaborate ill 



-tem. and especially of the great Sympathet ic 

 Turtle, have be. 1 by Mr. Swan, in his 



1 Comparative Anatomy of the Nerves, 1 4to., \ 



Here we must notice the experiments of Reili, which were perhaps 



