The orders in this class are chiefly distinguished from each other by the peculiar make of the bill and feet.

CLASS III, Amphibia, contains Amphibious animals, including what are commonly called reptiles. It is divided into four orders:

1st. With shells over their back, and four feet; as the tortoise and turtle.

2d. Covered with scales, and having four feet; as the crocodile and lizard.

3d. Body naked, destitute of feet; as serpents.

4th. The body naked, and having two or four feet; as the frog, and toad.

CLASS IV, contains Fishes, (Pisces,) natives of the water, unable to exist for any length of time out of it; swift in their motions, and voracious in their appetites; breathing by means of gills, which are generally united in a long arch; swimming by means of radiate fins, and mostly covered with scales.

Molluscous Animals.

CLASS V. Molluscous animals have soft bodies without bones; their muscles are attached to a calcareous covering called a shell, which is supposed to be formed by the secretions of the animal. This class are destitute of most of the organs of sense; the nauti lus and cuttle-fish are of the highest order of molluscous animals The oyster and clam are destitute of heads; they have a shell o two pieces, which are therefore termed bi-valved.

Articulated Animals.

We proceed next to those animals called Articulated; these have Jointed trunks, and mostly jointed limbs. They possess the faculty of locomotion, or changing place; some have feet, and others are destitute of them; the latter move by trailing along their bodies.

CLASS VI, Annelida, contains such animals as have red blood, without a bony skeleton; bodies soft and long, the covering divided into transverse rings; they live mostly in water; some of them secrete calcareous matter, which forms a hard covering, or shell; as the earth or angle-worm, and leech.

CLASS VII, Crustacea, contains animals without blood, with jointed limbs fastened to a calcareous crust; they breathe by a kind of gills. CLASS VIII, Arachnida, contains_spider-like animals, without blood, or horns with jointed limbs. They breathe by little openings, which lead to organs resembling lungs, or by small pipes distributed over the whole body; these do not pass through any important change of state, as insects do; they have mostly six or eight eyes, and eight feet, and feed chiefly on living animals; examples of this class are the spider and scorpion.

CLASS IX, Insecta, or insects, without blood, having jointed limbs and horns; they breathe by two pipes, running parallel to each other through the whole body; they have two horns; they are mostly winged, having one or two pairs; a few are without wings; mostly with six feet. They possess all the senses which belong to any class of animals, except that of hearing.

The winged insects pass through several changes or metamor phoses. The batterfly is first an egg; this, when hatched, is long and cylindrical, and divided into numerous rings, having many short legs, jaws, and several smail eyes; this is the larva, or caterpillar.

Class 3d-Class 4th-Molluscous animals-Articulated animals-Class 6th-- Class 7th--Class 8th-Class 9th--Metamorphoses of insects.

At length it casts off its skin, and appears in another form without limbs. It neither takes nourishment, moves, nor gives any signs of life; this is the chrysalis. In process of time, by examining it closely, the imperfect form of the butterfly may be seen through the envelope; this it soon bursts, and a perfect butterfly appears. When about to pass into the chrysalis state, of which they appear to have warning, the insect selects some place where it may repose safely during its temporary death.* The silk-worm spins a silken web for a shroud to wrap itself in, and from this all our silks are made.

CLASS X, Zoophites, or animal plants. Here we find the lowest beings in the animal kingdom. Some of the orders of this class contain animals which have neither heart, brains, nerves, nor any apparent means of breathing. These are sometimes called animal plants; many of them, as the corals, are fixed to rocks, and change place. The term coral includes under it many species; the red coral used for ornaments, is the most beautiful. The substance of coral, when subjected to chemical analysis, is found to consist chiefly of carbonate of lime; the hard crust which envelops the animal substance, is an excretion formed by it in the same way as the shells of the oyster and lobster are produced, or as nails grow upon the fingers and toes of the human body. The quantity of this carbonate of lime, elaborated by the little coral animal, is truly wonderful; islands are formed, and harbours blocked up by it. Fig. 158, a, represents a branching coral; the dots show the apertures by which the animal receives its nourishment. Some of the zoophites are fixed by a kind of root, to the bottom of the sea; some, as the sea-nettle, which appears like the segment of a circle, are carried about by the motion of the waters, without any voluntary motion, as are also the sea-daisy, sea-marygold, and the sea-carnation, so named from an apparent resemblance to those plants. We find here the sea-fan, the sea-pen, and the madrepore, the latter of which are often thrown together in vast quantities.

May not this be considered as a lesson to man to anticipate and provide for the change in his existence, which, his bodily infirmities and daily observation teach him, is to be his own lot?

Class 10th-Description of zoophites-Corals-Various kinds of zoophites

the sponge also belongs to this class of strange animal substances; it consists of a fibrous mass, containing a jelly-like substance, which when touched, discovers a slight sensation, the only sign of life manifested by it. There are many species of sponge; those most valued in the arts are found in the Mediterranean sea and Indian ocean. Some grow upon rocks, and are found covering the interior of submarine caves. The Spongia parasitica is seen grow ing upon the back and legs of a species of crab; sometimes as many as forty individual sponges extend themselves over the crab, impeding the motion of its joints, spreading like a cloak over its back, or forming for its head grotesque and towering ornaments, from which the poor crab vainly attempts to disencumber itself.

Some species of the sponge grow to a very large size; one has been found in the East Indies in the form of a cup, capable of containing ten gallons of water. The fibrous part of the sponge is the skeleton of the animal; the large apertures (see fig. 158, b,) serve to carry out fluids from within; while the water by which the animal is nourished, is imbibed by minute pores: this continual circulation of water is one of the most important functions of the living sponge. These animals resemble plants in their manner of producing others; they form a species of germ, like the bud growing upon the stalk; this falls off from the stem, and becomes a perfect animal. If a part of one of these animals is separated from the rest, it will itself be as perfect a living animal as was the whole before. A polypus can be divided into as many animals as it contains atoms; some of this order are very properly called hydras, (many-headed.) Besides these, there is another order of animal substances, infusoria, which appear like a homogeneous mass, having no appearance of any limbs whatever; these are either angular, oval. or globular.

COMPARISON BETWEEN ANIMALS AND PLANTS.

In our last lecture, after a glance upwards to the heavenly bodies, we returned to our globe, and considered its various substances; here we found two classes of bodies, inorganized and organized substances; the former including minerals, the latter embracing the animal and vegetable kingdoms. We then took a brief view of the animal creation.

At the head of the animal kingdom, we found man, sufficiently resembling brute animals in his material frame to constitute part of an extensive class, embracing the ape, elephant, and dog; yet between the lowest degree of intelligence in the human race, and the highest faculties of brutes, there is a line of distinction marked by the hand of the Almighty, in characters too obvious for doubt. God said, "Let us make man in our own image, and he breathed into him the breath of life, and man became a living soul."

Some writers have attempted to show that man differs only from the inferior order of animals in possessing a greater variety of instincts. But however wonderful may appear the instinctive perception of brutes, they are destitute of reason, and incapable of being

Sponge-Manner in which these animals are reproduced-Recapitulation-Man at the head of the animal kingdom-How resembling inferior animals.

244

COMPARISON BETWEEN ANIMALS AND PLANTS.

the subjects of moral government; we must, therefore, both from our own observation and the declarations of scripture, infer, that the faculties of man differ not in degree only, but distinctly in their nature, from those of all other beings upon our globe.

"Man, (says Buffon,) by his form and the perfection of his organs, and as the only being on earth endowed with reason, seems properly placed at the head of the kingdom of nature. All, in him, announces the lord of the earth; his form marks his superiority over all living beings; he stands erect, in the attitude of command; he can gaze upon the heavens; on his face is imprinted the character of dignity; the image of his soul is painted upon his features, and the excellence of his nature penetrates through his material organs, and animates the expression of his countenance."

In the orders of animals nearest to man, we find the senses of sight, touch, taste and smell, equally perfect as those possessed by him, and in some cases they are even more acute; but as we proceed downwards through the gradations of animal existence, we perceive the number and acuteness of the senses to diminish-we find some beings with but four senses, some with three, others with two, and lastly, in Zoophytes, we find only the sense of touch, and that so faintly exhibited as almost to lead us to doubt its existence. Let us now return to the distinction between animals and vegetables. You now perceive that although you would find no difficulty with regard to a nightingale and a rose, to discover to which of the king doms of nature they belong; yet with respect to a sponge or coral, a mushroom or lichen, it would be somewhat difficult, without a previous knowledge of their classification, to say which is called animal, and which vegetable, or to give the distinctions between them. We have seen among the zoophites, that the polypus, like a vegetable, may be increased by cutting shoots and ingrafting them upon other animals.

With respect to sensation, some plants seem to possess this, apparently even in a greater degree than some of the last orders of animals; the sensitive plant shrinks from the touch; the Dionea suddenly closes its leaves upon the insect which touches them; the leaves of plants follow the direction of light, in order to present their upper surfaces to its influence; as you may observe in flower pots placed by a window. The seed of a plant, in whatever situation it may be placed in the earth, always sends its root downwards, and its stem upwards; in these cases, does there not seem as much appearance of sensation and instinct, and even more, than in the lower orders of animals?

We find, then, that the possession, or want of instinct, does not constitute a mark of distinction between animals and plants.

Some have attempted to draw a line of distinction, by considering that locomotion, or the power of changing place, belongs to animals only; but this criterion seems to fail, since we find animals fixed to the bottom of the sea, or growing upon rocks, and plants moving upon the surface of the water.

Another mark of distinction has been given, in the supposed presence of nitrogen in animals, detected by a peculiar odour when animal substances are burning, similar to what we perceive in the combustion of bones; but nitrogen having been discovered in some vegetables, this proof is no longer considered infallible.

It appears then, from a comparison between animals and vegetables, that these beings are closely connected by the essential charac

How differing from them.

ters of organization; that it seems impossible to distinguish them by any trait that belongs exclusively to either; that the connexion between them appears the most striking in the least perfect species of both kingdoms; and that as we recede from this point, the differences become more numerous and more marked.

We may illustrate this view, by imagining two ascending chains, rising from one common point, each side of the chain becoming more and more unlike in proportion to the intervening distance from the centre. From this same central point, also proceeds the chain of inorganized substances; some imperfect animals resembling plants in their outward form, some, both of animals and plants, resembling minerals in their hard and calcareous coverings and shapeless forms.

Having thus learned the almost imperceptible gradations by which the animal and vegetable kingdoms are blended, we must, in stating the important differences which exist between animals and plants, consider the imperfect species of both kinds as exceptions to any general rule, and confine ourselves to perfect animals and plants.

1st. Plants differ from animals with respect to the elements which compose them; carbon, hydrogen, and oxygen, form the base of vegetable substances; animals exhibit the same elements, with this impor tant distinction, that carbon prevails in plants, and nitrogen in animal food.

2d. They differ in their food; plants are nourished with inorganized matter, absorbed with water, which holds in solution various substances; animals are mostly nourished either by vegetable or other animals.

3d. Plants throw off oxygen gas, and inhale carbonic acid; animals, in respiration, inhale oxygen gas and throw off carbonic acid. 4th. Although plants and animals both possess a principle of life, it is in the one case much more limited than in the other; exhibiting itself in plants by a feeble power of contraction or irritability; in animals appearing in sensation, muscular movement, and voluntary motion.

We see, then, many important differences between perfect animals and perfect plants. We have, in numerous instances, pointed out striking analogies between the two great divisions of organized bodies: this subject might be greatly enlarged; but we have already, amid the multitude of interesting facts and reflections presented by the vegetable creation, far exceeded the bounds originally prescribed. A few remarks on the inorganic matter upon and around the earth, and our course of Lectures is closed.

Inorganic bodies form the solid base of the globe. Minerals are spread upon the face of the earth, or lie buried beneath its surface. They form vast masses of rocks, chains of mountains, and the ground upon which we tread. The Water óccupies a still greater surface of the earth than the land; it is filled with life and animation; the treasures and wonders of the deep seem almost unbounded. The Air, lighter than earth and water, extending on all sides about forty miles in height, surrounds the whole globe, separating us from the unknown elements which exist beyond it. Heat, or Caloric, is a subtle fluid which pervades all matter, in an increasing proportion from solids to fluids, and fluids to gases. Light, reflecting its hues from terrestrial objects, produces, by the decomposition of its rays all the beautiful variety of colouring.

Result of the comparison between animals and vegetables-Chains of beings proceeding from one point-Differences between animals and plants-Different kinda of inorganic matter-The Deity manifested in his works.