OF THE LUMBRICUS, OR EARTH-WORM

TRIBE*.

Some of these worms bore into the earth, others live in mud, and others in the sand of the sea-shores. They are furnished with numerous prickles, which are short, and curved backward. These aid their movements in the ground. Their bodies, likewise, are covered with a viscid matter, which transudes through numerous pores, and assists their progress.

THE DEW-WORM†, AND LUG-WORM ‡.

The most insignificant insects and reptiles are of much more importance, and have much more influence in the economy of nature, than the incurious are aware of; and, notwithstanding their minuteness, they are mighty in their effects, from their numbers and fecundity. Dew-worms, in appearance, constitute a small and despicable link in the chain of nature; yet, if this link were destroyed, it would make a lamentable chasm. For, to say nothing of many species of birds and quadrupeds that are supported by them, worms seem to be the great promoters of vegetation. They bore, perforate, and loosen the soil, and render it pervious to rains

The Earth-worms have a round, annulated body, with generally an elevated fleshy belt near the head. Most of the species are rough, with minute concealed prickles, situated longitudinally, and have in the body a lateral aperture or pore.

+ DESCRIPTION. The Dew-worms have a prominent, annulated belt, at about one-third of their length. The fore part of the body is cylindrical, and the rest depressed. They are of a red colour, and furnished with eight lines of prickles.

SYNONYMS. Lumbricus terrestris. Linnæus.-Lob-worm, Garden-worm, or Twatchel.-Le Lombaie terrestre. Cuvier.

DESCRIPTION. This worm differs from the preceding chiefly in having two papillæ at the back of each segment of its body, bearing a small bristle in each.

SYNONYM. Lumbricus marinus,

Linn.

and the fibres of plants, by drawing straws and stalks of leaves and twigs into it; and chiefly, by throwing up infinite numbers of lumps called worm-casts, which form a fine manure for grass and corn.

Gardeners and farmers express their detestation of worms: the former, because they render the walks unsightly, and make them much work; and the latter, because they imagine that worms eat their green corn. But these men would find that the earth without worms would soon become cold, hard-bound, and void of fermentation; and consequently steril. It should also be observed, that green corn, plants, and flowers, are not so much injured by worms, as by many species of insects in a larva state; and by unnoticed myriads of those small shell-less snails called slugs, which silently and imperceptibly make amazing havoc in the field and garden. Lands that are subject to frequent inundations are always poor: one great reason of this may be, because all the worms are drowned.

The body of the Dew-worm is formed of small rings, furnished with a set of muscles, which act in a spiral direction, and enable it, in the most complete manner possible, to penetrate into, or creep upon the earth. The motion of these creatures may be explained by a wire wound on a cylinder; where, when one end is drawn on and held fast, the other, if loosed, will immediately follow. These muscles enable them with great strength to dilate or contract their bodies. The annuli or rings are also each armed with small, stiff, and sharp beards or prickles, which they have the power of opening out, or closing to their body. And under the skin is secreted a slimy matter, which they emit at the perforations between the rings, to lubricate the body, and facilitate their passage into the ground.

Dew-worms make their casts in mild weather, principally about the month of March or April. In rainy nights they travel about upon the ground, as appears from their sinuous tracks, on a soft, muddy soil. This they probably do in search of food. When at night

they appear on the turf, although they considerably extend their bodies, they do not quite leave their holes, but keep their tails firmly fixed, so that on the least alarm, they can precipitately retire under the earth. Whatever food lies within their reach, when thus extended, such as blades of grass, or fallen leaves, they seem content with it.

Helpless as they may appear, these creatures are very vigilant in avoiding such animals as prey upon them. The mole, in particular, they avoid by darting to the surface of the earth the instant they feel the ground move. Fishermen who are acquainted with this circumstance, catch them in great numbers, by moving the earth with a dung-fork in places where they expect to find them. When, however, they are wanted for fishing, they are perhaps most easily caught by the light of a lantern in the night, after heavy showers, on grass walks and sheep pastures, where the herbage is short.

In winter these worms retire very deep into the earth, to secure themselves from being frozen. They do not become torpid during this season; for often, in the intervals of mild weather, they are observed to throw up their casts, in the same manner as at other times of the year.

Lug-worms are marine animals. They frequent those parts of sandy sea-coasts which are left dry by the ebbing of the tides. Here they bury themselves deep in the sand, throwing up a kind of hillock over their holes, in the same manner as the Dew-worms. The fishermen employ them as bait for whiting, cod, and other fish.

OF THE LEECHES IN GENERAL.

The body of the Leech is oblong and truncate, or appears as if it were cut off at both ends. These animals are cartilaginous, and move by dilating the head

and tail, and contracting themselves into the form of an arch.

Some species are viviparous: others are oviparous, and lay their eggs on aquatic plants, or carry them under their belly. Each egg contains many young-ones. Several of the smaller kinds may be multiplied by cutting.

THE MEDICINAL LEECH*, AND HORSE-LEECH t.

In stagnant ponds and ditches these animals are most commonly found. Their body is formed with numerous annular wrinkles, which they have the power of expanding or contracting at pleasure. The tail ends in a circular muscle or sucker, which, when applied to any substance, readily adheres, by the animal's drawing up the middle, so as to have it pressed firmly down by the external air. By this it fastens itself with ease and security, while it extends the other part of its body in any direction; and it is so firmly fixed, that it can move its head about to seek for nourishment, without any danger of being carried away by the strength of the current. When the Leech is desirous of moving onward, it extends its body, fixes its head in the same manner that it did its tail; then loosens and draws that up; and again fastens it near its head, as a fresh point to proceed from.

The head of the Leech is armed with three teeth, of a

DESCRIPTION. This species of Leech is of an olive black colour, with six yellowish lines above, and spotted with yellow beneath. It is generally two or three inches in length,

SYNONYMS. Hirudo medicinalis. Linnæus.-La Sangsue des Chirurgiens. Cuvier.-Sangsue médicinale. Bosc.

+ DESCRIPTION. The Horse-leech is of an olive-brown colour, with an ochry yellow margin on each side. It is paler beneath than above, and is sometimes marked with a few black spots.

SYNONYMS.

Bosc.

Hirudo Sanguisuga.

Linn.-Sangsue noir.

slightly cartilaginous substance, which are so situated as to converge when the animal bites, and leave a somewhat triangular mark on the skin. These teeth are sufficiently strong to pierce the skin of an ox or a horse. Through the holes it forms with them, it sucks the blood: this is done by contracting the muscles of the throat, so as to make the blood rush through the vacuum above the wound into the stomach, a kind of membranaceous receptacle, divided into twenty-four small cells. Here the blood remains, sometimes for months, and affords support to the animal during the whole time. It passes off by transpiration, the matter fixing on the surface of the body, and afterwards coming off in small threads. In proof of this, if a Leech be immersed in oil, (where it may be kept alive for several days,) and afterward put into water, a kind of slough will be seen to loosen from its skin, exactly of the shape of the body.

The poor people in several parts of the south of England, collect Leeches for sale, and keep, for that purpose, many thousands together, in casks or tubs of spring water. This they change twice a day; or when they are in small numbers, about once in two days. They carefully wash away all the slime and filth which 'exude from the bodies of the animals. Violent noises are said to be very injurious to Leeches; particularly thunder-storms, after which they often die in great numbers. The effluvium of drugs also is said to be hurtful to them.

It is stated, that a large-sized Leech will generally draw about an ounce of blood. These animals will sometimes adhere so long, and become so much distended, as afterwards to die in consequence. They are, at any time, easily loosened from the skin, by putting upon them salt, pepper, or acids.

The Leech is a viviporous animal, producing one young at a time, and this about the month of July. If confined in a glass and kept in a room, it usually appears very restless before a change of weather.