The winter is passed by our common horse-leech in a state of torpidity, in the mud at the bottom of the ponds or ditches in which it lives.

The Earth-worms represent another tribe. In them suctorial discs, such as those of the leeches, do not exist; but a mechanical contrivance of a different kind may be observed. The rings, of which their body is composed, are no longer perfectly smooth, but are furnished with small bristles or hooks. These, as the creature pushes its way, catch upon the soil, and form fixed points of support, by which the worm is enabled to maintain its place while drawing forward the remaining parts of the body. Earthworms move but little abroad during the day-time, except when disturbed. The young are produced from eggs, which, previous to their being deposited by the mother, have undergone a certain degree of development.

The mouth of our common Earth-worm has a sharp proboscis, but is destitute of teeth. The food consists of the decaying particles of animal and vegetable matter, which instead of being dissolved and lost, become thus the means of supporting animal life. The results do not, however, stop here, but extend to birds and fishes, and even to man himself. This did not escape the observation of White of Selbourne, who justly remarks:

"The most insignificant insects and reptiles are of much more consequence, and have much more influence in the economy of nature, than the incurious are aware of; and are

mighty in their effect, from their minuteness, which renders them less an object of attention, and from their numbers and fecundity. Earthworms, though in appearance a small and despicable link in the chain of nature, yet, if lost, would make a lamentable chasm. For, to say nothing of half the birds, and some quadrupeds, which are almost entirely supported by them, worms seem to be the great promoters of vegetation, which would proceed but lamely without them, by boring, perforating, and loosening the soil, and rendering it pervious to rains and fibres of plants, by drawing straws and stalks of leaves and twigs into it, and, most of all, by throwing up such infinite numbers of lumps of earth called worm-casts, which, being their excrement, is a fine manure for grain and grass."

Respiration, both in the Leech and in the Earth-worm, is carried on by means of pores and internal sacs. In the "lob-worm," or "lug" of fishermen (Fig. 28), a portion of the body is furnished with little tufts, to which the blood is conveyed, and there purified, by coming into contact with the air diffused through the sea

water.

In the next tribe of Annelids, a new modification of these organs is exhibited, one admirably

Fig. 28. ARENICOLA.

adapted to their peculiar habits and modes of life. All the individuals of this assemblage dwell in tubes, consisting either of shelly matter, secreted from their own bodies, or of particles of sand and gravel glued together to serve as a habitation. Under these altered circumstances, the only place to which the vivifying principle of the sea-water could freely have access, would be that near to the orifice of the tubes; and here, accordingly, we find the respiratory apparatus arranged, often extremely graceful in its form, and enriched with brilliant colouring. The small contorted tubes which encrust, in so fantastic a manner, the old bottles or dead shells dredged up from any of our bays, form an example of this group. They are the dwellings of worms bearing the name of Serpula (Fig. 29). If while the animals are still alive, they be placed in a vessel of sea-water, few spectacles are more pleasing than that which they exhibit. The mouth of the tube is opened by the raising of an exquisitely constructed door, and the beautiful fan-like breathing apparatus is then cautiously extended.

The members of the fourth tribe present, in their habits, a complete contrast to the last. They are formed for loco

motion, and some among them can swim with considerable swiftness (Fig. 30). The roving life they lead has induced

S

Fig. 30.-NEREIS.

Milne Edwards to bestow on them the characteristic appellation of Errantes.

In respect to some worms, there are traditionary errors which are still current. Thus, there is a species, called the Hair-worm, which is abundant, during a part of the summer, in rivulets in the North of Ireland and elsewhere. Its length is about eight or ten inches, and the common superstition about it is, that horse-hairs placed in water become vivified, and are changed into these worms. This notion, with the addition that the Hair-worm was the young state of the serpent, was prevalent in the days of Queen Elizabeth, for we find it is thus recorded by Shakspeare,

"Much is breeding,

Which, like the courser's hair, hath yet but life,
And not a serpent's poison."

Among these humble animals are some which possess luminous properties. One has been observed in Ireland on

some of the extensive tracts of bog; and Mr. R. Ball, when passing at night between the islands of Arran, in the Bay of Galway, had an opportunity of observing a similar power in one of the marine species. As soon as the dredge was let down, a blaze of light flashed from the grass-wrack, with which the bottom was covered; and as the boat was pulled along, "the dredge seemed as if filled with liquid molten silver." On drawing it up, the light was found to proceed from numbers of a very small species of worm, of a bright red colour, and so soft that they could not be taken out of the dredge. By day-light, it is probable, their very existence would have been unnoticed, so little conspicuous were they.

CLASS II. BARNACLES AND ACORN SHELLS.

CIRRIPEDA.

"There are found in the north parts of Scotland and the islands adjacent, called Orchades, certain trees, whercon do grow certain shells of a white colour, tending to russet, wherein are contained little living creatures; which shells in time of maturity do open, and out of them grow those little living things, which, falling into the water, do become fowls which we call Barnacles."

THESE words occur in Gerardes' "Herbal, or General History of Plants," a work published in 1597; and the statement is given by that author on the authority of others. He then