cerearia is another class, imperceptible to the ordinary sight, yet found to be a real existence, pellucid, and furnished with a tail.* Ten other genera of the same order of miniature beings, but with a full and distinct individuality of animal life, have also been traced, studied, and delineated; all unknown to our more distant ancestors, and only revealed to our knowledge by the astonishing powers of the microscope and of the luminous fluid.t

All the orders mentioned in this Letter consist of invertebrated animals, or those which have no vertebra. They appear, to those who estimate importance by size, to be insignificant things; but magnitude is no criterion of either life or mind. The trees of the forest spring from the little corculum in their seeds. In that small spot their vital principle, organization, and qualities are abiding. Animals likewise emerge from the larger space of the maternal ova. So that the infusoria which the natural eye cannot see, or beholds only as a shining point, are not very much less than that speck in the embryo of the lion or the man, which the vital principle of both, and the soul of the latter, first occupy and animate. This is as great a mystery as it is a certainty. We see the fact; however incompetent we may be, in our present ignorance, to comprehend or explain it.

surrounded with short hairs. The sol species is found in water which has been kept some time; its body round, crystalline, dilatable, and contractile, with divergent rays of hairs longer than the diameter of its body. The linter appears in infusions of old grass. It varies in shape, and sometimes has rotatory motions. The innata of salt-water has a contractile funnel form. The lynceus appears in water which has been kept some time: its intestines are said to be eminently visible. Sixty specimens of this genus have been named.-T. Linn. 703-710.

Of its 13 species, the gyrinus occurs in animal infusions. The inquieta in salt-water. This kind changes its shape into a spherical, long, or oval figure, but always preserves its tail. The mutabilis is found in stagnant pools in such innumerable myriads as to cover the whole surface with a shade of green or red. The catellus appears in water where flowers have been kept. The head moveable; the abdomen twice as long as that, and filled with intestines. The tenax is in water with which the teeth have been washed.-T. L. 710-712

†These are the gonum, the colpoda, the paramecium, the cyclidium, the vibrio; leucophra, bacillaria, enchelis; volvox, so named from its quick rotatory motions; and the monas, the most simple of all know animated beings. Of this genus, the termo occurs in most animal and vegetable infusions. "Of all known animals, it is the most minute, being so extremely delicate and transparent, as often to elude the most highly magnifying powers, blending, as it were, with the water in which it swims."-Dr. Turton's Linn. p. 712-724.

Mind can exist in a point, as well as in the giant form into which that vital speck gradually enlarges.

But this division of animated nature has not in most of its classes the same number of organized senses which the creatures of greater bulk possess, as M. Cuvier has remarked.* Yet all these inferior orders exhibit indications of sentient, feeling, thinking, willing, and acting mind, as well as more important animals. In the mollusca order, the luna calendula sinks of its own volition into a hole when disturbed.† The holutheria genus contract or expand as they please. The larger species of the medusa, when touched, produce a slight tingling and redness in the hand of the molester; and one of its kinds, on feeling contact, contracts itself into the form of an apple. A new mollusca has been found to form a thread to guide it back to its shell when it moves from it.

"In the invertebrates, the senses are seldom to be met with all together in the same object. The cephalopods have no smell. Several gasteropods can neither hear nor see. The animals of bivalve shells have neither eyes, nor ears, nor smell; and the zoophytes, and the races below them, have, it is affirmed, only the single sense of touch, which in them is so extremely delicate, as to be acted upon even by light.— Kirby, vol. iv. p. 235. Cuvier, Anat. Comp. vol. ii. p. 362.

†Turt. Linn. 105. Mr. Hughes says of this sea marigold: "I often attempted to pluck one from the rock to which they are affixed, but could never effect it. As soon as my fingers came within two or three inches, it would immediately contract, and shrink back into the side of the rock. If left undisturbed for two or three minutes, it would again gradually come into sight, expanding, though at first very cautiously; but would again contract with surprising quickness when my hand approached."-Hughes, Nat. Hist. Barbadoes.

T. Linn. 108. When the echini are alarmed, they immediately move all their spines towards the object, and wait an attack, as an army of pikemen would present their weapons.-Bingl. 303.

The cucumis of the Greenland sea. p. 112. The sea anemonies, though destitute of eyes, are evidently affected by light; for if a candle be held over the glasses in which they are kept at such a distance as to communicate no heat, yet they regularly close, and do not open again till the light is removed. Two of them contested for a piece of fish, like dogs for a bone. The Abbé Dicquemare so placed it, as that two anemonies had each hold of an end. Each swallowed on till their mouths came in contact. They struggled for three hours which should retain the share it had taken, till the gray one lost its hold. The yellow then slowly absorbed the rest. The gray made one more attempt; but before he could fasten on it, the other, by a final effort, sucked in the end.-Bingl. 294.

Mr. Rang, who has made a new monographie of the aplysia genus, has remarked a new genus of molluscas gasteropodes, which he calls litiopa. This little animal climbs up marine plants, and leaves its

In the testacea order, the argo of the argonautæ genus, the admired nautilus, when it means to sail in its little shell, discharges from it that quantity of water which made it heavier than the marine fluid around it, and by this act, rising to the surface, erects its arms and expands the membrane between them to catch the air, and the breeze then drives it forward like a vessel under sail; while it hangs down two others of its arms over its shell, to serve as oars or as a guiding rudder.* One species of the snail, as winter approaches, covers the aperture of its shell with a calcareous lid, as if to keep itself from the cold. The solon not only moves its shell into the sand, and raises it by a dexterous use of its powers, at its will, but also gives a striking instance of its persisting determination to avoid a danger it has experienced.‡

Among the zoophytes, the sponge absorbs and rejects water from its small mouths and its tormentosa species, stings and raises blisters on the hand that meddles with it.|| The tubularia fabrica has not the power to protrude its body from its coral tube, but it expands its cirri beyond it when the tide covers it ; and its stellaris species, whenever the water is in the least degree agitated, retracts its fine

shell to do so; but keeps attached to it by spinning out a thread, on which it returns to it when it pleases.-Bull. Univ. 1831, p. 377....The thread is the guide it provides for itself back to its home.

* T. Linn. 304. In some places, where the sea is not agitated by winds, great numbers are occasionally seen diverting themselves by thus sailing about. On the least alarm, they retract their arms, and take in as much water as will sink their vessel, and disappear downwards. In this escape they are so quick, that Le Vailant's people, with all their care and speed could never catch one.-Bingl. 326.

† Ib. 513. The slug, in order to descend safely to the ground from the branch of a tree, causes a flow of viscous secretion towards its tail, where it forms it into a thread, which it lengthens to the necessity, at the rate of an inch in three minutes. Bingley, An. Biog. vol. iv. p. 282.

This razor-fish, to sink into the sand, makes its tongue into a little shovel to form a hole, and then into a hook, to sink that deeper, till it has buried itself sometimes two feet. When it chooses to regain the surface it shapes its tongue into a ball, and pushes up its shell.

Ib. 65. When a little salt is thrown into its cell, it rises up immediately from it; and will, on this excitation, come to the surface as often as it is applied; but if it be once seized by the hand, and afterward allowed to retire into its hole, the salt will be strewed in vain, for it will never make its appearance again. Bingl. 314. Ib. 659. 1 Ib. 668,

white cirri within its tube.* The coral architects rival the bee in skill, perseverance, and exactness.

Among the infusoria, the urceolaris B. that seems but a small white speck, has a double rotatory organ, which it protrudes or conceals at its own pleasure. So the vorticella convallaria, though only a white point to the naked eye, can suddenly contract its stem in a spiral manner, and in a moment expand itself again,- -as the inclinans species occasionally contracts itself to half its length. The bomba trichoda moves with velocity, and assumes various shapes.§ The vibrios, from paste and blighted wheat, are like little eels, and very prolific.|| The petty volvox even enter into personal combat, like two angry quadrupeds. T

Many of the other infusoria change frequently the shape of their minute bodies; all apparently the actions of spon taneous volition. As far as the movements of all these classes of petty animals can be understood, they seem to be those of a vital principle of the same kind with that which insects, fish, and the other brute animals possess. Several of these three orders of marine beings can live without additional nutriment, as many fish seem also to do.** Their

* Ib. 669. The madrepore animals, "when undisturbed, protrude themselves from their cases, and oscillate from left to right with an extremely quick motion. On any alarm, they immediately withdraw inwards, and nothing is to be seen but the naked stem and branches.”— Bingl. 338.

+ lb. 693. It is frequently found on the stalks of duckweed. Ib. 697, 698.

Ib. 703. So the vermicularis dilates and contracts itself.-705. In the latter part of the year they are oviparous; at other seasons they produce live offspring. Their most gigantic individuals are seldom one-tenth of an inch long. If grains of blighted wheat be soaked for a few hours, they appear in great numbers even when the wheat has been kept dry for years.-Bingl. 353.

Le Martiniere detached two from the rest: "Like two strong and active wrestlers, they immediately rushed together, and attacked each other on every side. Sometimes one would dive, leaving the adversary on the surface of the water: one would describe a circular movement, while the other remained at rest in the water. Their motions at length became so rapid as no longer to allow me to distinguish the one from the other."-La Martin. Ap. Bingl. 356.

** Even the slugs can exist for a great length of time, for several months successively, without food.-Bingley, An. Biog.vol. iv. p. 281.... Sea anemonies lived about twelve months without any other food than the sea-water, though they would swallow pieces of a muscle offered to them.-Ib. 293....When the pholas pierces the marble and lodges in it, growing too large to get out by its hole, it is sufficiently nourished by the sea-water overflowing upon it.—Ib. 310.

external configurations greatly differ from those of the rest of animated nature; but it is a pleasing proof that one Creator has made the whole, and upon one grand general system of construction, although this has been surprisingly diversified in its specific details, that the more exactly these inferior orders are studied, the greater analogy is found to prevail between them and the rest of the sentient kingdoms.*

LETTER XII.

The Bird Creation-Their Plumage and Song-Power of Flight, and Migrations-Numbers and Classes-General Character-and Mental

Faculties.

A NEW System of exterior figure, and a new species of beauty, in the three main sources of the beautiful in material things, and to the surveying eye-form, motion, and colour-arose to visible existence in the feathered creation. From the same causes of agreeable emotions, the fish excite pleasurable sensations in those who gaze upon their placid activity in the calm and clear ocean. And these feelings arise also within us as we handle the shells of the testacea, which are always so neat in figure, polish, hues, and completeness, and often impressively interesting in their most lovely tints and more elegant shapes; all announcing the refined taste and minute execution of their invisible designer. But the BIRDS eminently surpass all the marine classes in their appeals to our sense of beauty in their attractive appearance. Form, motion, finish, and colour are the elements of what is beauteous in both orders of being: but the

* M. G. Cuvier observes of the cephalopodes division of the mollusca, that "they have a brain inclosed in a distinct cavity; eyes; ears in the form of two mandibules; a tongue, salivary glands, an esophagus, a throat, a second stomach, an intestinal canal, a liver, heart, arteries, veins, nerves, and the reproductive organs, in common with other vertebrated animals; but all differently disposed, and mostly organized in a different manner.”—Bull. Univ. 1830, p. 310.

M. le Baron de Ferussac is preparing, and has begun to publish, his Histoire Naturelle des Mollusques, under the orders of the cephalopodes, pteropodes, and gasteropodes. It will be the completest work on the subject that has yet appeared.

Y