We cannot better describe the Annulose animals than in the words of Lamarck; he calls them,
“Animals with soft bodies, lengthened, worm-shaped, naked, or inhabiting tubes, with the body divided into segments, or at least transverse wrinkles, often without head, without eyes, and without antennÆ, unfurnished with articulated limbs, but the greater number having, instead, small protuberances, bearing spines, and capable of being retracted at pleasure, disposed in rows along the sides, though not continued quite to the extremity of the body, and assuming various forms. They have also red blood circulating by veins and arteries; this separates them from the Worms, properly so called, which have white blood. This colour of the blood is a singular fact, since the animals are much less complex in their organization than the Mollusca, which have colourless blood. The Class of Annulose animals has been separated into three Orders, namely, Annulata sedentaria, which are fixed to other substances; Annulata antennata, possessing antennÆ, or feelers; and Annulata apoda, without projecting members answering as feet, serving solely to attach the animal to rocks, stones, &c.”
Shells of various sedentary Annulose Animals.
ORDER ANNULATA SEDENTARIA,
(Sedentary Annulose Animals.)
The creatures which form this order are generally found attached to rocks, shells, &c. and are usually of small size. The engraving represents a variety of species of these animals. Of the genus Serpula there are many species, but as it is in general merely the shell that is found in collections, they are but ill defined; some of the species are found in almost all climates. The animal of the Serpula has great power of contracting its body, but it never leaves its shell or tube; this tube is gradually lengthened by the inhabitant, who always occupies the most recently-formed portion of it; its operculum, the lid with which it closes the opening of its tube, is very prettily formed; it is something like the mouth-piece of a trumpet, but of course not perforated, and it closes the opening with great accuracy.
The Magnificent Amphitrite,
(Amphitrite magnifica.)
This beautiful species is perhaps the largest of the whole tribe as yet discovered. It is found in various parts of the coast of Jamaica, adhering to, or rather embedded in, the rocks. Its irritability is exceedingly great, and on being approached it instantly retreats into its elastic tube; this tube is of a leathery consistence, unlike that of the Serpula. Specimens of this elegant species can only be obtained by breaking off such parts of the stone as contain them. These, being put into tubs of sea-water, may be kept for months in perfect health. That part of the body which is so beautifully spread out like an umbrella, consists of the branchiÆ or organs of breathing; these are of a yellowish colour, beautifully marked with pink. The Amphitrite, although perhaps it never entirely leaves its tube, is not attached to it, and frequently draws out nearly the whole of its body.
ORDER ANNULATA ANTENNATA,
(Annulose Animals possessing AntennÆ.)
The Sand-Worm of the Fishermen,
(Arenicola piscatorium.)
This Worm forms its nest in the sand on the sea-shore, and is much sought after by fishermen as bait for fishes. It is found in all the European seas. There appears to be but one species, but that is met with in great abundance.
Blood-coloured Leodice, (Leodice sanguinea.)
The antennated Annulata differ materially from those which are enclosed in a case; they possess, in addition to their antennÆ, organs of motion, like the false legs of a caterpillar, and two or four well-formed eyes; they are all marine animals, and altogether they bear a strong resemblance to the scolopendra, or centipede.
The species represented above was taken on the southern coast of Devonshire; it is the largest English species, extending sometimes to the length of fourteen or fifteen inches.
When the animal was in a glass of sea-water, the circulation of the blood through the bristle-like appendages on each side of the body was a curious object, and appeared to be effected at the will of the animal, but when it became sickly, the circulation was slower, and as soon as it expired all the colour from those parts vanished.
The mouth is large, and placed beneath, concealing most formidable jaws, or complicated fangs, which were put forward occasionally as the animal became sickly, or in the agonies of death. The figure beneath the worm shows the shape of this singular apparatus.
The Spinous Sea-Mouse, or Sea-Caterpillar,
(HalithÆa aculeata.)
The Sea-Mouse is found in the European seas, and when in its native element is singularly beautiful, the hair with which it is partially covered being equal in splendour to the colours on the tail of a peacock.
ORDER ANNULATA APODA,
(Footless Annulose Animals.)
The greater portion of the Annulose animals, namely those already described, are furnished with small projecting points on the sides of their body, which assist them in their motions, and which may, consequently, be considered as supplying the place of feet; but those we have yet to notice have no similar appendages, and, therefore, they are called footless. They are all very lively in their movements, and live either in moist earth, or the mud at the bottom of ponds. We find among the footless Annulata two well-known genera, namely, the Earth-worm and the Leech.
The Common Earth-Worm,
(Lumbricus terrestris.)
The body of the Earth-worm is composed of a great number of narrow rings, and along each side are four rows of very small, short, silk-like bristles, of a substance partly horny and partly shell-like. These bristles are placed on the edges of the rings, and it is by the alternate contraction and expansion of these rings that the worm is enabled to move along, the little bristles acting like hooks, and so forming various fixed points of resistance or fulcra, upon which the animal can rest at each movement forwards. The organization of the Earth-worm is very simple, the intestinal canal for the food being a simple straight tube, except in one part of its length, where a kind of gizzard is found, which answers the purpose of a stomach. It is supposed to feed upon the vegetable substances it finds in the earth.
The hole, or burrow, formed in the earth by the worm, always has two openings, one by which it enters, and by which it throws out the dirt which is removed during the progress of its excavation, and the other by which it sometimes leaves its burrow, so that the hole made by the animal would be much in this form, descending at a, and reaching the surface by b. It has been said, that the Earth-worm, if divided by the spade or otherwise, will unite again and live; the foundation for this appears to be the more probable fact, that, when divided, that portion of the animal in which the head is placed may, perhaps, survive the mutilation, and ultimately again become a perfect creature.
Although worms, after wet weather, sadly disfigure our gravel walks, they are, at the same time, useful gardeners, loosening the earth round the roots of plants, and thus rendering it more capable of receiving the small fibres of the roots. During the Winter they penetrate very deeply into the ground, and remain, according to Latreille, rolled up in a kind of nest, protected from injury by the discharge of mucus, which is furnished by the pores of their body.
The Earth-worm appears to have been a considerable favourite with the author of the Journal of a Naturalist; among other remarks, he observes, “There is another creature, and that a very important one in the operations of nature, that is surrounded by dangers, harassed, pursued incessantly, and becomes the prey of all; the common Earth-worm. This animal, destined to be the natural manurer of the soil, and the ready indicator of an approved staple, consumes on the surface of the ground, where they soon would be injurious, the softer parts of decayed vegetable matter, and conveys into the soil the more woody fibres, where they moulder and become reduced to a simple nutriment, fitting for living vegetation. The parts consumed by them are soon returned to the surface, whence dissolved by frosts, and scattered by rains, they circulate again in the plants of the soil,
Death still producing life.
“Thus eminently serviceable as the Worm is, it yet becomes the prey of various orders of the animal creation, and perhaps is a solitary example of an individual race being subjected to universal destruction. The very emmet seizes it when disabled, and bears it away as its prize. It constitutes throughout the year the food of many birds; fishes devour it greedily; the hedgehog eats it; the mole pursues it unceasingly in the pastures, along the moist bottoms of ditches, and burrows after it through the banks of hedges, to which it retires in dry seasons. Secured as the Worm appears to be by its residence in the earth, from the capture of creatures inhabiting a different element, yet many aquatic animals seem well acquainted with it, and prey on it as a natural food, whenever it falls in their way: frogs eat it, and even the great water-beetle I have known to seize it, when the bait of the angler, and it has been drawn up by the hook. Yet notwithstanding this prodigious destruction of the animal, its increase is fully commensurate to its consumption, as if ordained the appointed food of all.
“Worms, generally speaking, are tender creatures, and water remaining over their haunts for a few days, drowns them. They easily become frozen, when a mortification commences at some part, which gradually consumes the whole substance, and we find them on the surface a mass of jelly. Their retiring deeper into the soil is no bad indication of approaching cold weather; but no sooner is the frost out of the ground, than they approach the surface.
“Earth-worms do considerable mischief to the floriculturist by drawing the young plants, immediately after they are transplanted, into the earth. In the drainage of lands they are of essential service, penetrating the clay that lies beneath the vegetable mould in every direction, and thus forming numerous small canals to carry off the water into the deep trenches dug by the agriculturist.” The author we have already quoted, after concluding this account of the Worm, says, “I would advocate the cause of all creatures, had I the privilege of knowing the excellency of them; not willingly assigning vague and fanciful claims to excite wonder, or manifesting a base pride by any vaunt of superior observation; but when we see, blind as we are, that all things are formed in justice, mercy, truth, I would tell my tale as a man, glory as a Christian, and bless the gracious Power that permitted me to obtain this knowledge.”
The Medicinal Leech, (Hirudo medicinalis.)
The medicinal utility of the Leech seems, even in very remote times, to have been acknowledged by mankind, and accordingly we find it noticed in the writings of many ancient physicians. It was not simply applied to the cases in which it is at present employed, but was recommended to be used in many singular ways: a paste made of the ashes of a burnt leech was said to have the property of removing the hair from any part of the body. It was also employed to suck the blood from a wound occasioned by a mad dog, or any other rabid animal.
At present the employment of this useful creature is confined to the operation of drawing blood from inflamed parts of the surface of the body, for which use it is eminently adapted.
There are as many as twelve or fifteen species of these creatures, but only two have been employed in medicine, namely, the Hirudo medicinalis, which may be known by having six yellowish lines, or striÆ, on its back, while the under part is of a grayish hue spotted with black, but, as we shall presently see, these markings are not uniformly found; and the Hirudo troctina, of a brownish colour, the upper part of the body marked with black spots, each of which is surrounded with a golden-coloured ring, the sides of a dingy yellow, and the under part of a yellowish green with black spots.
The first of these species, the medicinal leech, is common throughout the whole of Europe, but is much more abundant in the Southern parts; it is generally about three inches in length. Formerly it was very abundant in Great Britain, but the improvements in agriculture, and the consequent drainage of the land, together with the great use made of it in medicine, have of late years rendered it of less frequent occurrence. On this account great quantities of leeches are imported; these chiefly come from Bourdeaux and Lisbon. On a moderate calculation, it appears that, in England, on an average, out of every hundred leeches employed, ninety-nine may be considered of foreign production; these differ from the English leech in being somewhat larger, and having the under part of a uniform colour, without spots. Some idea may be formed of the number of leeches used in medicine by the statement, that in the hospitals of Paris alone, 300,000 were employed in one year. The prevailing colour of the medicinal leech appears to vary according to the nature of the soil on which it is found. In Winter the leech retires to waters of considerable depth, and seeks shelter in the mud at the bottom; but in the Summer it appears to delight in shallow pools, basking, as it were, in the warmth of the sun: but if the water it frequents is in danger of being dried up by the Summer-heat, the leech buries itself in the mud at a considerable depth. Just before a thunder-storm, leeches appear much agitated, and rise frequently to the surface of the water; this, therefore, is considered by the leech-gatherers as a favourable time for collecting them.
The property by which a leech anticipates thunder, has induced some persons to employ it as a species of barometer; for this purpose a leech is enclosed in a glass vessel half-filled with water, and the following is supposed to be the result. When the weather is about to be serene and pleasant, the leech will remain at the bottom of the vessel without the least movement; secondly, if it is about to rain, the animal will rise to the surface, and there remain until the approach of fine weather; thirdly, before boisterous weather, it will appear in a state of great agitation; fourthly, on the approach of thunder, it will remain out of water for several days, appearing agitated and restless, and so on.
This natural barometer appears to answer tolerably well, if there is sufficient belief in its virtues on the part of the possessor, and if one leech only is employed; but when several of these creatures are enclosed in the same vessel, they do not appear to obey the same laws, and, consequently, their movements do not correspond with sufficient accuracy to render their indications of the weather of much use.
The medicinal leech appears during its whole life to exist on the blood or other juices of the creatures on whose body it fixes itself; this is not the case with the horse-leech, which lives entirely on the larvÆ of aquatic insects, worms, &c., so that the common idea of the danger of the bite of the horse-leech is without foundation.
The horse-leech is exceedingly voracious, not only swallowing worms, tadpoles, &c., but even preying upon its own species. Sixty-five horse-leeches were placed in a glass vessel, and in five days the number was reduced to fifty-two, and not a vestige of those that were missing was to be discovered.
The usual slowness of action of the digestive powers in all animals of cold blood, was curiously illustrated in the case of a horse-leech, which, after swallowing two small leeches of a different species, disgorged one of the two at the end of three days, in a living state, and apparently not much injured from its sojourn in so unusual a lodging; but it enjoyed its liberty only for a few hours, its more powerful companion swallowing it a second time at the end of that period.
A number of this species of leech, inhabiting the water that supplied a trough in which a tench had been placed, fixed themselves to different parts of the body of the fish, and so effectually was the poor tench annoyed, that it was soon deprived of life. “The leeches then tore it (previously breaking the line of connexion between the various parts of the body, by inflicting a vast number of bites or wounds,) into such pieces as they could readily receive into the stomach, and so diligent were they, that in a few days nothing remained of the fish but the mere skeleton.”
From these habits it would appear, that the name of Hirudo sanguisuga, (the blood-sucking leech,) has been improperly applied to the horse-leech; on this account a recent author has suggested the name of Hirudo vorax, (the voracious leech,) as being more suitable to its nature.
Leeches are supposed to be very long-lived; two were preserved in confinement for eight years before they died, and the well-ascertained slowness of their growth seems to place their length of life beyond a doubt.
On the head of the medicinal leech ten points are arranged in the form of a horse-shoe, thus—
These are considered, by some authors, to be organs of sight, or eyes, while, on the other hand, it is stated by others, that they are merely tubercles. Lamarck was of this opinion, and, consequently, in describing their character, says they are without eyes.
The teeth, or rather piercers, with which the leech is furnished, are three in number, of a hard gristly substance, and so placed, with regard to each other, as to meet in the centre at equal angles; these piercers are thrust into the skin when the animal attaches itself; not by one plunging effort, but by constantly scratching or sawing upon the surface (assisted at the same time by the sucking action of the lips); in this manner they gradually become buried in the skin, and there remain as long as the creature retains its hold; this movement of the piercers occasions the gnawing pain felt for the first two or three minutes after the leech has commenced operation.
Leeches are at times so scarce and valuable, that great care has been taken in preserving them in a healthy state and fit for use. The principal art in managing them consists in placing them in vessels sufficiently large, keeping the water clear, and in removing those which are unhealthy as soon as they are discovered.
Leeches, when applied to the skin, frequently show little inclination to bite, and many plans have been resorted to, to induce them to commence operations, such as bathing the part with milk, &c.; but these methods may be considered useless, and the best plan appears to be, to wash the part clean, and this is the more necessary when any embrocation has been previously applied; but the surest way is to puncture the place slightly, so as to cause the blood to appear. If the little surgeon, before it is fully gorged, appears lazy and unwilling to proceed, it can be usually roused by being sprinkled with a little cold water.
After a leech has fallen off, it is usual to sprinkle salt on it to induce it to disgorge the blood it has swallowed; but as the salt frequently blisters its body, it has been recommended by Dr. Johnson of Edinburgh, from whose work on the Leech, we have obtained most of the preceding information, to apply a small portion of vinegar to the head of the leech instead of salt.
The necessity for obliging the leech to dislodge the blood it has swallowed, arises from the fact that it would remain in the body of the animal for some months before it could be all digested; but the most singular thing is, that, during the whole of this time, the blood remains in nearly as fluid a state as when it was newly swallowed[5]. The stomach of this creature is very curiously formed, being composed of a number of chambers, each chamber having a separate connexion with the intestinal canal, in such a manner that, at the will of the animal, the contents of each chamber can be emptied singly into that canal, through a distinct opening.
It was long a matter of dispute as to whether leeches were produced from eggs or born alive, but it is now ascertained that the ova are developed in a singular case, having some resemblance to the cocoon of a silkworm. The following engraving represents this case, of its natural size: fig. 1, shows the perfect case or cocoon, and fig. 2, the same opened, with the young leeches contained within it; it is said that, at times, there are as many as thirteen or fourteen in one case. This cocoon is formed by the parent animal, and by it deposited in the mud or clay, which composes the bed of the pool it inhabits.
The fact of the young leech being produced from these cocoons, although only latterly ascertained by naturalists, was long since well-known to the dealers in leeches on the French coast, who avail themselves of this knowledge of their habits, to multiply them for the purpose of sale. “It was by these means the leech-dealers of Bretagne, and particularly in Finisterre, replenished the ponds in which they preserved those leeches which were intended for the Paris market.
“About the month of April or May, according to the nature of the season, they send out labourers, provided with spades and baskets, to the little muddy marshes, where they are known to exist in abundance. These workmen then set about removing those portions of mud that are known to contain cocoons, which are afterwards deposited in sheets of water previously prepared for their reception; here the young leeches quit the cocoons, and are allowed to remain for six months, when they are removed to larger ponds.” While they remain in these ponds, the cattle and other animals are driven to the water, for the purpose of allowing the young to feed upon them, as it is supposed that they grow much more rapidly after having partaken of blood.
There is a small species of leech in the island of Ceylon, which is more dreaded, and, from its great numbers, produces more evil, than even the venomous reptiles which are found in the island, including the terrible hooded snake itself.
The largest of these leeches are seldom more than half an inch in length, and the smallest are minute indeed. This leech is a very active animal; it moves with great rapidity, and is even said occasionally to spring. It is supposed to have an acute sense of smelling, for no sooner does a person stop where leeches abound, that they appear to crowd eagerly to the spot from all quarters. In rainy weather, it is shocking to see the legs of men on a long march thickly beset with these creatures, gorged with blood, and the blood itself trickling down in streams. It might be supposed there be little difficulty in keeping them off; but they crowd to the attack, and fasten on more quickly than they can be removed. Their bites are much more troublesome than would be imagined, being very apt to fester and become sores, and, in persons of a bad habit of body, to degenerate into extensive ulcers, and ultimately cause the loss of a limb, if not that of life itself.
Many plans have, of course, been resorted to, to avoid this pest, such as anointing the legs with tobacco-water, grease, &c., but all to very little purpose, the only successful mode appearing to be, the enclosing the lower part of the legs in boots and pantaloons, fitting very closely to the limb, a very unpleasant dress in so sultry a climate.
