THE form of the cockle-shell is slightly heart-shaped, with spinous ribs; it inhabits the European seas, and is of a white or tawny colour, with white bands; the grooves deep, about eighteen, and wrinkled near the hinge; the prickles grow larger from the middle towards the circumference.

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The cockle is represented in the above figure with the foot, or hook, protubed, in order to take its nourishment: and by help of the elastic power of which it can jerk itself from place to place; and in this manner, when it happens to be left by the tide, it regains its proper element. touched ever so gently when lying in this attitude of evident enjoyment, it withdraws the hook, and closes in the twinkling of an eye. Lobsters and crabs lie in wait for this opportunity of thrusting in a leg or a claw, whereby they kill and secure the cockle for food; but it often happens that the younger ones of those crustaceous animals, not being sufficiently hardened or matured to withstand the violent snapping of the shells on their close, lose the limb; and herein we see the abundant wisdom of Providence, in bestowing on them the power of renewing their members when cut off; and, but for which, the whole race would soon become extinct, since this mode of procuring food subjects them to eternal warfare.

THE OYSTER.

THIS genus comprehends the two extensive families of pectens, or scallops, and oysters; and there are no less than a hundred and thirty-six species in the whole. In both divisions the animal is well known as a nutritive and valuable food. Both scallops and oysters are found plenti

fully in the Indian Seas, the Mediterranean, the American Ocean, and in the European Seas, where they constitute a considerable article of commerce. The scallops grow a sort of coarse byssus; and have the agility of leaping full half a yard out of the sea, at which time they open their shells, and spout out the stale water within them; after which they rapidly sink, taking in fresh water, and closing their shell with a loud snap, which betrays their beds to the watchful fisherman.

The difference between the oyster and the scallop is obviously impressed by the hand of nature; but its movements, both in the water and out, is still more contrary; for when left dry by the tide, by a sudden closing of its valves, assisted by the foot, it has the power of springing four or five inches at a jerk, repeating this motion in order to regain its element. In the water, it has the power of raising and sustaining itself near the surface, turning about in various directions, and on any alarm, suddenly closing the valves and sinking to the bottom.-The oyster, on the contrary, is unfurnished either with a foot or with byssus; and its powers of motion consist only in turning either the flat or convex side upwards or downwards; and even to effect this, the animal' is said to take advantage of the force of the ebbing or flowing of the water to assist it.

The oyster excludes its young completely formed; and by the help of a magnifier, the joinings of the little infant shells can be distinctly seen, with all their parts as perfect as the parent animal, though appearing to the naked eye only as a minute point.

THE colour of the rattle-snake, which is bred both in North and South America, but in no part of the old world, is a yellowish brown above, marked with broad transverse bars of black. Both the jaws are furnished with small sharp teeth, and the upper one has four large incurvated and pointed fangs; at the base of each is a round orifice, opening into a hollow that appears again near the end of the tooth in the form of a small channel; these teeth may be raised or compressed. When the animals are in the act of biting, they force out of a gland near the roots of the teeth, the fatal juice; this is received into the round orifice of the teeth, conveyed through the tube into the channel, and from thence, with unerring direction, into the wound. The tail is furnished with a rattle, consisting of joints loosely connected; the number of these is uncertain, depending in some measure on the age of the animal, being supposed to increase annually by an additional joint. The young snakes, or those of a year or two old, have no rattle at all.

As the tail of these snakes, which are the most dreaded of all serpents, keep rattling upon the slightest motion, strangers are thus providentially warned of their approach. In fine weather, the notice is always given, but not always in rainy weather; this inspires the Indians with a dread of travelling among the woods in wet seasons. In addition to this circumstance, the odour of the rattle-snake is so extremely foetid, that when it basks in the sun, or is irritated, it is often discovered by the scent before it is either seen or heard. Horses and cattle frequently discover it by the scent, and escape to a distance; but when the serpent happens to be to the leeward of their course, they sometimes encounter its

venom.

Rattle-snakes are viviparous, producing their young, generally about twelve in number, in the month of June, and by September these acquire the length of twelve inches. It has been well attested that they adopt the same mode of preserving their young from danger as that attributed to the common viper, receiving them into their mouth and swallowing them.

THE BOA.

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THE ground colour of the body of this animal, which is the largest and strongest of the serpent race, is yellowish large chain-like, redish brown, and sometimes perfectly grey, on which is distributed, along the back, a series of

red variations, with other small and more irregular marks and spots. They are easily distinguished from other serpents by the under surface of the tail being covered with undivided plates, like those on their belly; and their body not being terminated by a rattle. There are three species, natives of Africa, India, the larger Indian islands, and South America, where they chiefly reside in the most retired situations, in woods and marshy retreats.

The great boa is frequently from thirty to forty feet in length, and of a proportionate thickness; but, happily for mankind, the rapacity of these creatures is often their own destruction; for whenever they seize and swallow their prey, they seem like surfeited gluttons, unweildly, stupid, helpless, and sleepy; they at the same time seek for some retreat, where they may lurk for several days together, and digest their meal in safety. The smallest effort will then destroy them; they scarcely can make any resistance; and, equally unqualified for flight or opposition, even the naked Indians do not fear to assail them. But it is otherwise when this sleeping interval of digestion is over: they then issue, with famished appetites, from their retreats, and with accumulated terrors, while every animal of the forest flies from their presence. They never, however, bite from any other impulse than that of hunger, and when they do, their bites are destitute of venom.

THE COMMON ENGLISH SNAKE.

THE ringed, or black snake, which is the most common and largest of the English serpents, sometimes exceeds four feet in length. The neck is slender; the middle of the body thick; the back and sides covered with small scales; the belly with oblong, narrow, transverse plates: the colour of the back marked with two rows of small black spots, running from the head to the tail; the plates on the belly are dusky; the scales on the sides are of a blueish white; the teeth are small and serrated, lying on each side of the jaw, in two rows. The whole species is perfectly inoffensive, taking shelter in dunghills, and among bushes in moist places, whence they seldom nemove, unless in the midst of the day, in summer, when they are called out by the heat to bask themselves in the sun. If attacked, they at first endeavour to escape, but