others, such as the common lizard, are found basking in the sun on barren heaths. The crocodile tribe shall at present be selected as a specimen of this order. Nature, says Lacépède, has granted to the eagle the higher regions of the atmosphere; has given to the lion for his domain the boundless deserts of the hot climates of the world; and has abandoned to the crocodile the shores of the sea, and of the mighty rivers of the torrid zone. These immense animals, living equally upon the inhabitants of the sea, and on those which the earth nourishes, exceed in size every other creature of their own order. They divide their prey, neither with the eagle, as the vulture, nor with the lion, as the tiger, but exercise a domination greater than either. They are less easily extirpated, as their property of frequenting both land and water enables them more readily to avoid the snares of their enemies. The low temperature of their blood, too, which endues them with the power of sustaining hunger for a considerable time, places them less frequently under the necessity of braving danger for the sake of satisfying their appetite. Naturalists have added to the gavial of India, and the crocodile of Egypt, already mentioned, another distinct species, or rather family, that of the alligator of America. In all these three regions of the world, where extensive swamps and lagoons exist under a burning sun, or broad rivers flow slowly, through low and reedy banks, these monstrous animals dispute possession with man, their only formidable enemy. "In Louisiana," says an American author, speaking of the alligator, "all our lagoons, bayous, creeks, ponds, lakes, and rivers, are well stocked with them; they are found wherever there is a sufficient quantity of water to hide them, or to furnish them with food; and they continue thus, in great numbers, as high as the mouth of the Arkansas River, extending east to North Carolina, and as far west as I have penetrated. On the Red River, before it was navigated by steam-vessels, they were so extremely abundant, that to see hundreds at a time along the shores, or on the immense rafts of floating or stranded timber, was quite a common occurrence, the smaller on the backs of the larger, groaning and uttering their bellowing noise, like thousands of irritated bulls about to meet in fight; but all so careless of man, that, unless shot at, or positively disturbed, they remained motionless, suffering boats or canoes to pass within a few yards of them without noticing them in the least. The shores are yet trampled by them in such a manner, that their large tracks are seen as plentiful as those of sheep in a fold." The insensibility to the presence of man evinced by the alligator on the banks of the Red River, is only one instance of a fact well known to travellers, that, in unfrequented parts of the earth, that dread of the human race, which seems instinctive to the lower animals where they mingle with man, is almost unknown. Cowper beautifully alludes to this remarkable circumstance in the soliloquy he puts into the mouth of Robinson Cru soe, "I am out of humanity's reach; I must finish my journey alone; I start at the sound of my own! Their tameness is shocking to me." The common crocodile is the species well known as frequenting the rivers of Africa. In the central parts of that continent, they are said to attain the enormous size of the gavial of India. On the banks of the Nile, however, their dimensions are smaller, it being a striking fact, that where man has taken up his abode, all the animals hostile to his prosperity dwindle in size, and become diminished in ferocity, owing probably to their circumscribed bounds, and the privations to which they are subjected by the tremendous force and influence of human reason. These animals are capable of being tamed. Bruce mentions, that in Abyssinia children may be seen riding on their backs; and it is a well known historical fact, that the priests in the temple of Memphis in Egypt, in the celebration of their heathen mysteries, were in the habit of introducing tame crocodiles to the deluded multitude as objects of worship. They were fed from the hands of their conductors, and decorated with jewels and wreaths of flowers. What may be the precise office assigned to these horrid creatures in the economy of the Author of Nature, it may be difficult to say. That they belong to the class intended as checks on over-production, is sufficiently evident; and that the existence of some such devourer of animal life in the prolific regions which they haunt, is, upon the whole, a blessing, it is not difficult to conceive. The alternative of animals increasing in numbers, till they die of starvation as they are produced, is too distressing to be reflected on without shuddering; and yet, unless there were a system of checks, such as we find to exist in carnivorous animals, this would be the necessary result. One of the ways in which this check practically operates in the case of the alligator, may be understood by attending to the following graphic description of its operations during the dry season, given by the traveller from whom I have already quoted: “ Each lake has a spot deeper than the rest, rendered so by those animals, who work at it, and always situated at the lower end of the lake, thereby insuring themselves water as long as any will remain. This is called by the hunters the alligators' hole. You see them there lying close together. The fish, that are already dying by thousands, through the insufferable heat and stench of the water and the wounds of the different winged enemies constantly in pursuit of them, resort to the alligators' hole to receive refreshment, with a hope of finding security also, and follow down the little currents flow ing through the connecting sluices. But no! for as the water recedes in the lake, they are here confined. The alligators thrash them, and devour them whenever they are hungry; while the ibis destroys all that make towards the shore." There is a strange mixture of wisdom and folly in the human character; and the latter quality can scarcely be exhibited in stronger operation, than when it erects the crocodile or the serpent into an object of religious worship, and causes intelligent man to bow the knee before the lowest and most malignant orders of the brutes. It exemplifies, however, this important truth, that terror takes a prominent place in the devotions of unenlightened men, and is, indeed, the groundwork of all superstitious belief. It is not till the human mind is emancipated and enlarged by revelation, that this emotion is changed into the ennobling feeling of veneration, or gives place to the still more exalted and generous sentiments of love, gratitude, and pious confidence. I can make no exception in favour of the deist of the present day, both because his religious feelings, when they exist at all, are very often unconsciously modified and enlightened by a Christian education, and because, when that is not the case, they consist either in cold abstractions, or in a feeling of mere sentimentality. SEVENTH WEEK-SATURDAY. REPTILES. THE TORTOISE. THERE is yet another species of reptile which seems to demand some notice, on account of the peculiarity of its structure, differing as it does from all other orders of vertebrated animals, and approaching in its form nearer than any other to animals very low in the scale of organization, while it retains the essential characters of its own natural division;-I allude to the order chelonia, which comprises all the tribes of tortoises and turtles. This order, instead of presenting a skeleton wholly internal, exhibits a conformation, in which the trunk of the body is enclosed on every side by a bony case, which leaves openings only for the head, the tail, and the fore and hinder extremities. Although this structure bears some resemblance to that of the echinus and the crustacea, yet the substance which forms the outward defence is a real osseous structure, developed in the same manner as other bones, subject to all the changes, and having all the properties of these structures. Security seems to have been the object of the Author of Nature in this mode of formation, and for its attainment a vaulted and impenetrable roof has been constructed, capable of resisting enormous pressures from without, and proof against any ordinary measures of assault. On It is curious to remark, that, in the accomplishment of this design, nature has been true to the type of vertebrated animals, even while that design rendered a new arrangement and an apparent anomaly necessary. examination, we find that all the bones composing the skeleton in other vertebrated animals exist also in the tortoise; and that the bony case which envelopes all the other parts, is really formed by an extension of the spinous processes of the vertebrae and ribs on the one side, and of the usual pieces which compose the sternum on the other. "It is scarcely possible," says Dr Roget, "to have stronger proofs, if such were wanting, of the unity of plan which has regulated the formation of all animal structures, than those afforded by the skeleton of the tortoise."* The tortoise class has been divided into four great families, one inhabiting salt water, two others fresh water, and a fourth living entirely upon the land. In all of them the same intention is manifested, that of protecting an inert animal from the attacks of its numerous foes. * Bridgewater Treatise, vol. i. p. 465. |