man seems not equal to the life of the most minute species. In the royal ponds at Marli, in France, there are some particular fish which, it is said, have been preserved tame since the time of Francis the First, and which have been individually known to the persons who have succeeded to the charge of them ever since that period.

Fish, like land animals, are either solitary or gregarious. Some, as Trout, Salmon, &c. migrate to considerable distances in order to deposit their spawn. Of the sea-fish, the Cod, the Herring, and many others, assemble in immense shoals, and migrate in these shoals through vast tracts of the

ocean.

In the Gmelinian edition of the Systema Naturæ, the Fishes are divided into six orders:

1. Apodal; with bony gills, and no ventral fins, as the Eels.

2. Jugular; with bony gills, and ventral fins before the pectoral ones, as the Cod and Haddock.

3. Thoracic; with bony gills and ventral fins placed directly under the thorax, as the Turbot, Sole, Perch, and Mackrel.

4. Abdominal; with bony gills, and ventral fins placed behind the thorax, as the Salmon, Pike, Herring, and Carp.

5. Branchiostegous; with gills destitute of bony rays, as the Pike-fish and Lump-fish.

6. Chondropterygious; with cartilaginous gills, as the Stur geon, Shark, Skate, and Lamprey.

INSECTS.

The Insect division of the animal world received its name from the individuals of which it is composed having a separation in the middle of their bodies, by which they are cut, as

it were, into two parts. These parts are in general connected by a slender ligament or hollow thread.

Insects breathe through pores arranged along their sides*; and have a scaly or bony skin, and many feet. Most of them are furnished with wings. They are destitute of brain, nostrils, and eyelids. Not only the place of the liver, but of all the secretory glands, is, in them, supplied by long vessels that float in the abdomen. The mouth is in general situated under the head; and is furnished with transverse jaws, with lips, a kind of teeth, a tongue, and palate: it has also, in most instances, four or six palpi, or feelers. Insects have also moveable antennæ, which generally proceed from the front part of the head, and are endowed with a very nice sense of feeling.

In a minute examination of this class by Professor Cuvier, neither a heart nor arteries have been detected; and this gentleman says that the whole organization of insects is such as we might have expected to find, if we had previously known that they were destitute of such organs. Their nutrition, therefore, seems to be carried on by absorption, as is the case with the polypes, and other zoophytes+.

Nearly all Insects (except Spiders, and a few others of the apterous tribe, which proceed nearly in a perfect state from the egg) undergo a METAMORPHOSIS, or change, at three different periods of their existence.

The lives of these minute creatures, in their perfect state, are in general so short that the parents have seldom an opportunity of seeing their living offspring. Consequently, they are neither provided with milk, like viviparous animals, nor are they, like birds, impelled to sit upon their eggs in

The Crab and Lobster tribes form an exception to this rule, for they respire by means of gills.

+ He excepts the Crabs and Lobsters, which he arranges in a class by themselves, and denominates Crustaceous animals.

order to bring their offspring to perfection. In place of these, the all-directing Power has endowed each species with the astonishing faculty of being able to discover what substance is fitted to afford the food proper for its young; though such food is, for the most part, totally different from that which the parent itself could eat. Some of them attach their eggs to the bark, or insert them into the leaves of trees and other vegetable substances; others form nests, which they store with insects or caterpillars that will attain the exact state in which they may be proper food for their young ones, when they shall awaken into life; others bury their eggs in the bodies of other insects; and others adopt very surprising methods of conveying them into the body, and even into the internal viscera of larger animals. Some drop their eggs into the water, an element in which they would themselves soon be destroyed. In short, the variety of contrivances that are adopted by insects to ensure the subsistence of their offspring, are beyond enumeration.

From the eggs of all insects proceed what are called larvæ, grubs, or caterpillars. These consist of a long body, covered with a soft, tender skin, divided into segments or rings. The motions of many of the larvæ are performed on these rings only, either in the manner of serpents, or by resting alternately each segment of the body on the plane which supports it. Such is the motion of the larvæ of Flies, emphatically so called, and of Wasps and Bees. Sometimes the surfaces of the rings are covered with spines, stiff bristles, or hooks: this is the case in Gad-flies, Crane-flies, and some others. The bodies of the larvæ, in some orders of insects, have, towards the head, six feet, each formed of three small joints; the last of which is scaly, and terminates in a hook: this is usual in those of Beetles and Dragon-flies. The larvæ of Butterflies and Moths, besides six scaly articulated feet, have a variable number of other false feet, which are not jointed, but terminate in hooks disposed in circles and semicircles. These hooks, which are attached to the skin by a kind of retractile

tubercles, serve as cramps to assist their motion on other bodies. The larvae of such insects as undergo only a semimetamorphosis, as Locusts, Crickets, and Cockroaches, and those of insects that undergo no transformation, as the Spiders, Ticks, and Mites, do not differ, with respect to their feet, from the perfect insects. In this larva state many insects remain for months, others for a year, and some even for two or three years. They are, in general, extremely voracious, oftentimes devouring more than their own weight in the course of twentyfour hours.

As soon as all their parts become perfected, and they are prepared to appear under a new form, called a pupa or chrysalis, most species of insects fix upon some convenient place, for the performance of this arduous operation. This is generally a place where they are not exposed to danger; for, in their transformation, they have neither strength to resist, nor swiftness to avoid, the attack of an enemy. That Power which instructed the parents to deposit their eggs in a proper receptacle, directs the offspring in the most secure and appropriate situation for their future defenceless state. Some of them spin webs or cones, in which they enclose themselves; others undergo their change in decayed wood; and others conceal themselves beneath the surface of the earth. Preparatory to the transformation, they cease to take any food, and, for some days, continue in a state of inactivity. During this time the internal organs are gradually unfolding themselves. When the completion is at hand, many of them may be observed alternately to extend and contract their bodies, in order to disengage themselves from the caterpillar skin. The hinder parts are those first liberated: when this is done, the animals contract, and draw the skin up towards their head; and, by strong efforts, they soon afterwards push it entirely off. In their chrysalid state they remain for some time, to

* The chrysalis is occasionally called Aurelia, Bean, or Cod.

all appearance, inanimate; but this is only in appearance, for, on being taken into the hand, they will always be found to exhibit signs of life. It is singular that, in the changes of insects, the intestinal canal is frequently very different in the same individuals, as they pass through the three states.

As soon as the animal, within the shell of the chrysalis, has acquired strength sufficient to break the bonds that surround it, it exerts its powers, and appears to the world in a perfect state. For a little while it continues humid and weak; but, as the humidity evaporates, its wings and shell become hardened, and it soon afterwards commits itself in safety to its new element.

Some writers have conjectured that the antennæ or horns of insects are their organs of hearing; for it is evident, from various experiments, that insects are possessed of this sense in a degree as exquisite as most other animals, although, from their minuteness, we perhaps may never discover by what The antennæ, however, seem little likely to answer the purpose of ears. These instruments, of apparently exquisite sensibility, appear adapted to very different purposes, but to purposes with which we may remain long unacquainted.

means.

The eyes of insects are formed of a transparent crustaceous set of lenses, so hard as to require no coverings to protect them. These, like multiplying glasses, have innumerable surfaces, on every one of which the objects are distinctly formed; so that, if a candle be held opposite to them, it appears multiplied almost to infinity on their surfaces. Other creatures are obliged to turn their eyes; but insects have always some or other of these lenses directed towards objects, from what quarter soever they may present themselves. All these minute hemispheres are real eyes, through which every thing appears topsy turvy.

M. Leeuwenhoek, with the aid of a microscope, used as a telescope, looked through the eye of a Dragon-fly, and viewed