back, and are very large in flat fish; their use, like the pectoral fins, is to keep the body well balanced, as well as to contribute to its forward motion. The anal fins are placed under the tail, enabling the fish to keep an upright position.

The chief instruments of a fish's motion are the fins, which in some fish are more numerous than in others. The fish in a state of repose, spread all his fins, and seems to rest upon its pectoral and ventral fins near the bottom. If the fish folds up either of its pectoral fins, it inclines to the same side. When it desires to have a backward motion, striking with the pectoral fins in a contrary direction effectually produces it. If the fish desires to turn, a blow from the tail sends it about, but if the tail strikes both ways the motion is forward.

In pursuance of these observations, if the dorsal and ventral fins be cut off, the fish reels to the right and left, and endeavors to supply its loss by keeping the rest of its fins in constant employment. If the right pectoral fin be cut off, the fish leans to that side; if the ventral fin, on the same side, be cut away, then it loses its equilibrium entirely. When the tail is cut off, the fish loses all motion, and gives itself up to where the water impels it.

The senses of fishes are remarkably imperfect, and indeed, that of sight is the only one which, in general, they may be truly said to possess. But this is, in some degree, compensated by their extraordinary longevity; several species being known to live more than a hundred years.

Such is the general picture of these heedless and hungry creatures; but there are some of this class living in the waters, that are possessed of finer organs and higher sensations; that have all the tenderness of

birds or quadrupeds for their young; that nurse them with constant care, and protect them from every injury. Of this class are the cetaceous order, or fishes of the whale kind. But the fierce unmindful tribe, who leave their spawn without any protection, are called the spinous, or bony kinds, from their bones resembling the sharpness of thorns.

If we emerge from the deep, the first, and most obvious class of amphibious animals that occur upon land, are frogs and toads. Then we find lizards of different kinds, as the crocodile, salamander, &c.

Frogs and toads, wherever they reside, seem equally adapted for living upon land, and in the water. The frog moves by leaping; the toad almost crawls upon the ground. The frog is light and active; the toad, slow and swollen, and incapable of much exertion. The frog is the best swimmer of all four-footed animals; the toad only creeps about in the mud.

The lizards are an awkward, ungainly tribe, differing from every other class of animals. Their color is very various, and very brilliant, and they differ very much in size and form; the crocodile being sometimes thirty feet in length, and the small chameleon, only an inch.

The crocodile is distinguished for its size and fierceness. There are two kinds; the crocodile, and the cayman, or alligator; the one being a native of the western, and the other of the eastern continent. These animals are seen lying on the banks of rivers for whole hours, and even days, so motionless, that one not used to them might mistake them for trunks of trees; but this mistake is often fatal; for the torpid animal, at the near approach of any living thing, darts upon it with swiftness, and drags it to the bottom. In this manner it seizes and destroys various animals, and is equally dreaded by all.

The salamander is a heavy torpid animal, very timid and inoffensive, and about eleven inches long. It is amphibious, and when taken in the hand is cold to a great degree. There are several other kinds of lizards, all differing from each other, as the iguana, chameleon, green lizard, flying lizard, variegated lizard, &c. Some of these are harmless, while others are to be dreaded for their bite, which makes a severe wound.

Serpents live to a great age, and some of them grow to an immense size. In Java, one of them readily destroys and devours a buffalo. The poor animal is first seized, and crushed to death in the folds of the serpent. The whole body being reduced to one mass, the serpent untwines its folds, licks the body all over to make it slip down his throat the more easily, and beginning at one end, by degrees, swallows a morsel, three times its own thickness. It then lies torpid for a long time, and may be approached and destroyed with safety.

The most material distinction between serpents, is, that some are venomous, and some are inoffensive; but not a tenth of their number are actually venomous.

From the noxious qualities of the serpent kind, it is no wonder that man, beasts, and birds carry on an unceasing war against them. The ichneumon and the peccary destroy them in great numbers, by seizing them near the head. The vulture and eagle also prey upon them in great numbers. Dogs also are bred up to oppose them.

In venomous serpents there are two large teeth or fangs issuing from the upper jaw. Wherever these are wanting, the animal is harmless; wherever they are found, it is to be avoided as a most pestilent enemy. The most venomous serpents of tropical climates are, the viper, the rattlesnake, the cabra de cabello, and the whip-snake. If a viper inflicts a wound, the symptoms are not without danger. Much more violent symptoms succeed the bite of a rattlesnake; but when a person is bitten by a cabra de cabello, he dies in an hour. The whip-snake is five feet long, and not thicker than the lash of a whip. It is exceedingly venomous, and its bite will kill a person in six hours.