any direction they please, or can moor themselves to the surface of sub-marine rocks.

The outer covering or "shell" of the Sea-urchin is not formed of one piece, as the name would lead us to suppose but of a multitude of pieces accurately fitted together, and which, by a beautiful contrivance, are made to enlarge with the progressive growth of the animal. It is impossible for a rightly constituted mind to contemplate the admirable mechanism of the spines and suckers, and the elaborate structure of the shell, without at once feeling the conviction that in them we behold a portion of "the works of the Lord, and His wonders in the deep." And this feeling increases with the increased minuteness of our examination.

The individuals of the fifth family are not likely to attract the notice of the casual observer. The English term, Seacucumbers (Fig. 25), gives some idea of their general form.

on them the spines have disappeared; but, as the covering of the body is soft, they can move by the extension or

D

contraction of its parts, as worms do; and, like the Seaurchins, they continue to employ the aid of suckers. It is an animal of this kind which the Malays of the Oriental Isles seek so diligently for the supply of the China market, where it obtains a good price when well preserved. It is employed by the Chinese in the preparation of nutritious soups, in common with an esculent seaweed, sharks' fins, edible birds'-nests, and other materials, affording much jelly. The members of the sixth family, in external appearance, resemble worms; but, from an examination of their internal structure, it is ascertained that they must, in reality, be classed among the Star-fishes. They are not furnished with suckers, and their movement is precisely the same as that which is displayed by worms (vermigrade). The English names of Tube-worm and Spoon-worm, have been applied to certain species. Some are found under stones, some burrow in sand, and some select as their mansion an empty univalve shell; their habits, however, are as yet imperfectly known.

ARTICULATED OR JOINTED ANIMALS.

ARTICULATA.

"Whatever creeps the ground,

Insect or worm; those waved their limber fans
For wings, and smallest lineaments exact
In all the liveries deck'd of summer's pride,
With spots of gold and purple, azure and green;

These as a line, their long dimensions drew,

Streaking the ground with sinuous trace."-MILTON.

THE Leeches and Worms belonging to this group present to the eye very much the same appearance as the worm-shaped animals which have just been mentioned among the Star-fishes. But an examination of the internal structure shows that they are essentially distinct. The nerves, as may be seen in the annexed figure (Fig. 26) of a common insect, are no longer arranged like rays, and the body in many tribes, as the Earth-worm and the

Millepede (Julus), consists of a repeti- Fig. 26.-NERVOUS SYSTEM tion of rings or segments. The Arti

OF CARABUS.

culated Animals are arranged in the following Classes:I. Leeches, Earth-worms, &c. Annellata.

II. Barnacles and Acorn-shells, Cirripěda.
III. Crabs, Lobsters, &c. Crustacea.
IV. Beetles, Bees, Butterflies, &c. Insecta.
V. Spiders, Scorpions, and Mites, Arachnida.

CLASS I.-LEECHES, EARTH-WORMS, &c.

ANNELLATA.

"Her divine skill taught me this,
That from everything I saw

I could some instruction draw,
And raise pleasure to the height,

Through the meanest object's sight."-G. WITHER.

THE most obvious character of the Leech or the Earth-worm is the number of little rings of which the body is composed; and hence the Latin word, which signifies a little ring, suggests an appropriate term for this class of animals.

The medicinal Leech and the common Horse-leech of our ponds are so well known, that every one must, at some period

Fig. 27-LEEch.

or other, have noticed that either extremity of the body can, at the will of the animal, be used as a sucker, and thus converted into a support or point of attachment. Leeches are of many species; but these peculiar discs or suckers may be regarded as "the badge of all the tribe."

The medicinal Leech is not a native of Ireland; it is found in some parts of Britain, but is now becoming very rare. It is still seen in the lakes of Cumberland, but even there is

rapidly disappearing. This fact is mentioned by Wordsworth in a stanza, which notices at the same time the manner in which they are collected:

"He with a smile did then his words repeat;
And said, that, gathering leeches, far and wide
He travelled; stirring thus about his feet
The waters of the pools where they abide.
Once I could meet with them on every side;
But they have dwindled long by slow decay;

Yet still I persevere, and find them where I may."
Resolution and Independence.

The supply of leeches used in these countries is derived from France, Sweden, Poland, Hungary, the frontiers of Russia, and Turkey, and the great extent of the trade thus carried on may be judged of from the fact, that four only of the principal dealers in London import 7,200,000 annually.

The term Leech was applied by our old writers, not only to the animal, but also to persons, both male and female, who were skilful in the art of healing. Thus, in the ancient Ballad of Sir Cauline, the king calls upon the princess to exercise her skill on behalf of the wounded knight :

"Come down, come down, my daughter deare,

Thou art a leeche of skille;

Farre lever had I lose half my landes,

Than this good knight sholde spille."