The young are hatched from eggs in about fifteen days after their exclusion, and remain for some time in a tadpole state, that is, with branchiæ for the respiration of water; these, however, become obliterated with the development of true lungs, so that, though the newt passes the greatest portion of its existence in the water, it is only at first that, like the tadpole of the frog, its respiration is fishlike; afterwards, the atmospheric air is breathed, for which it often comes to the surface. The food of the newt consists of the larvæ of aquatic insects, worms, etc., and it may be caught by means of a baited hook. During the winter, it hybernates, buried in the mud. pearing towards the middle of autumn. I become developed, and the faculty of inspiring the atmospheric air is acquired, for which the as yet aquatic animal may be observed to come to the surface, taking it into its mouth, and afterwards discharging below the surface in the form of a round bubble. The gills now begin to become obliterated; the tail, too, now less and less requisite for the purposes of locomotion, either aquatic or terrestrial, begins to shrink; it ultimately disappears, and the metamorphose is complete. The appearance and the habits of the animal have undergone an according change with the reversal of its physical constitution; and it is fitted either to leap among the grass of the meadow, or swim in the water, the atmospheric air being its sole element of respiration. Surely this marvellous process, performed with unvarying precision, cannot be uninteresting to the thoughtful inquirer into the laws that regulate the conditions of living beings; it bespeaks design, and a power which baffles human comprehension. We are surrounded with mysteries in creation; we see a little, we know a little, but beyond a certain point our utmost mental energies fail to pass. The transformations which the newt and the frog undergo in their organization, from the tadpole to the perfect state, are very curious, and those of the latter may be now contemplated with ease, as these little creatures abound in every ditch and pond, and are easily procured. The egg of the frog is a mass of round nutritive jelly, having a small black spot in the centre. By degrees this small spot enlarges, and exhibits the appearance of a round head to which a flattened tail is joined; this is the tadpole, and in this form it is hatched, and moves with celerity in its new element. At first a few filaments, or feathery tufts, appear on the sides of the neck, as in the annexed figure, which float loosely, and serve for the aeration of the blood by the air which the water itself contains. These filamentous appendages are, however, only temporary, and precede the formation of proper gills, which are four in number on each side, and closely resemble those of fishes. Thus organized as a fish, the animal increases in size; but in a few weeks, the hind legs begin to make their appearance, first beneath the transparent skin of the trunk, at the origin of the tail; these are succeeded by the fore legs; their development goes on progressively until they have acquired a degree of size proportionate to that of the head and body. During this period, the lungs have also But we must not leave the water without endeavouring to gain an acquaintance with other beings, the contemplation of which will fill our minds with astonishment. Let us take some of these small aquatic plants, with a little of the water in which they float, to our home, for the purpose of more minute examination. We shall scarcely fail to find on the leaves some singular polypes, the first discovery of which appears to have been made by Leuwenhoek in 1703, about the same time that a correspondent of the Royal Society made the same discovery in England, and described their singular mode of reproduction. In 1744, these polypes may be said to have been rediscovered by M. Trembley, of Geneva, who made known to science their wonderful properties, so repugnant to the established notions of animal life, that many regarded the alleged facts as impossible fancies. The polype to which we allude, is the hydra, of which four fresh-water species are known, hydra viridis, hydra vulgaris, hydra fusca, and hydra verrucosa. Of these, the first three are common in weedy ponds or slowly running streams; the two former, however, being the most abundant; the fourth has been taken in Ireland. while examining some aquatic plants It was that M. Trembley observed certain singu- | that the head part of a polype cut in two lar filamentous bodies adhering to their has been seen in a few minutes to exleaves, which at first he regarded as pand its tentacula, and catch prey as parasitic vegetables; but a closer exami- usual. nation convinced him that they were capable of locomotion; and he found also that they preyed upon small insects or crustacea, and were attracted by light. He now became assured that they were animals, and, delighted with the discovery, commenced a series of diligent investigations. The hydra, the most simple of organized beings, consists of a homogeneous gelatinous tube, contracted at one extremity, which may be termed its caudal, and which is furnished with a minute sucker, for the purpose of adhesion to leaves or stems; the other extremity, of which the orifice may be regarded as the mouth, is surrounded by a number of radiating, contractile filaments, (of singular length in hydra fusca,) which serve as arms of prehension. In the hydra viridis, these filaments, or tentacula, are scarcely equal to, or do not exceed, when elongated to their utmost, the length of the body. On submitting one of these animals to microscopic examination, which may be readily done, it will be found to consist of a granular structure invested by albumen; but neither nervous, nor muscular fibres, nor vessels of any kind can be discovered by the most minute attention; there are no rings as in the worm, nor any organs of the senses. The entire composition is gelatinous, with minute granules intermixed. Yet the animal is possessed of the powers of locomotion, appreciates the presence of light, by which it is sensibly affected, and is highly predatory and ravenous, waging warfare with beings far more complexly organized than itself; and is at the same time so tenacious of life, that if divided longitudinally or transversely, by means of a pair of fine scissors, or even cut into several parts, each part becomes a perfect animal. A polype cut transversely in three parts requires four or five days in summer, longer in cold weather, for the middle piece to produce a head and tail, and the tail to get a head and body, which they do pretty much in the same time; the head part appears to perfect itself sooner than the rest. It is extraordinary, that polypes thus produced grow much larger and are far more prolific than those not multiplied by artificial division. So little inconvenience do these operations seem to give, In the water of the rivers or clear ponds, which it naturally inhabits, the hydra is mostly found at the surface, or adhering to plants exposed to the light; it is indeed influenced by the light, which it invariably seeks; and when several are confined in a glass, they seek that side which is most illuminated. Hence, we may suppose that a highly refined degree of nervous sensibility, of which we can have no definite idea, resides in their whole composition, giving them a sense to us unknown. They also feel, and this power or property is peculiarly observable in their tentacula, which surround the mouth, and which are affected by the contact of other bodies, or even the smallest particles. These polypes, unlike most others, are capable of independent locomotion, and can wander about in the water according to circumstances. Their usual mode of proceeding along the stems or leaves of plants is, however, slow; fixing their caudal sucker, so as to attach themselves sesurely, they bend the body down with a gentle movement, describing a semicircle, till the mouth touches the surface of the leaf, or whatever it be, on which they are stationed; they then adhere by the mouth or the tentacula, unfix the caudal sucker, draw it close to the mouth, and there fix it; they then elevate the body, again bend it down and adhere by the tentacula, and bring the caudal sucker up to the mouth as before, and so on in succession. This mode of progression is so tedious, that a journey of a few inches requires several hours; they have, however, a more expeditious way, which consists of a series of somersets; adhering by the tentacula and the caudal sucker, they detach the latter, and instead of bringing it up to the mouth, throw it beyond, as far as possible, describing a semicircle, which being affixed, the same revolution is performed by the head. Free in the water, the hydra moves much more rapidly; suspended with its head downwards, its caudal sucker acting the part of a float on the surface, it is drifted with the current of the water, or wafted along by the breeze, or, grasping objects within its reach with its tentacula, it propels itself along; or, holding firmly by a stem or leaf, moors itself in a state of rest. When alarmed, or touched | with teeth, nor any other instrument That creatures of such unsolid structure should not only be voracious, but capable of seizing and swallowing quick and active animals, as insects and their larvæ, and even minute fishes, is calculated to surprise us: such, however, is the case. While watching for its prey, the hydra remains with its tentacula spread widely out and motionless, waiting till some luckless tenant of the water comes in contact with them; the moment an animal, fitted to become its prey, is brought into contact with one of these filamentous arms, its course is instantaneously arrested, and notwithstanding all its efforts to escape, it appears to be fixed as if by some power too great to be overcome; the tentacle contracts, others are brought into contact with the struggling captive, it is gradually dragged to the orifice of the mouth, which opens to receive it, and forced into the digestive cavity, where it may be seen through the transparent body of the hydra, until the process of digestion renders it indistinct, giving a dull opacity to the transparent body of the devourer. The power which the tentacles possess of thus arresting the animal's prey is not well understood. M. Trembley attributed it to a viscid secretion acting like birdlime; but it has been observed, that when the hydra is satiated with food, animals which then may be brought into contact with the tentacula are not arrested, but easily escape. It cannot be doubted, that the hydra is to be reckoned among poisonous creatures, being endowed with the power of instantly killing the softer animals on which it preys. Smellie states that small water worms, which the polypus is accustomed to attack, are so tenacious of life, that they may be cut to pieces without their seeming to receive any material injury, or suffer much pain from the incisions; but the poison of the polypus instantly extinguishes every principle of life and motion; strange to say, no sooner has the mouth of the polypus touched this worm than it expires. No wound, however, is to be perceived in the dead animal. By experiments made with the best microscopes, it has been found that the polypus is neither provided It would seem that the granules of the gelatinous body of the hydra, from their change of colour according to that of the prey, perform some important office in the assimilation of the nutritive particles of the food. The action of the digestive cavity upon the food received is very rapid; but the digestive powers of this stomach exert no influence on any part of the animal itself, as the tentacula, which in the long-armed species (H. fusca) are frequently coiled round the prey while undergoing digestion in the stomach: nor does one polype of the same species, if swallowed by a larger individual, appear to be subject to the operation of the digestive powers. On one occasion M. Trembley saw a contest between two of these creatures for the same prize, which both had seized, and both partially swallowed; the strife ended by the larger swallowing the smaller hydra, together with the subject of their mutual contention. The fate of the smaller hydra he regarded as certain; but no. After the devourer and the devoured had mutually digested their mutual captive, the swallowed hydra was disgorged from his imprisonment alive and sound, and apparently without having suffered any inconvenience. The reproduction of these animals is plant-like, by gemmules or buds, which sprout indifferently on any part of the animal's body, gradually assume their true form, and become detached and independent. The annexed sketches present us with the two species of this singular polype. 1. The green hydra, (hydra viridis,) in various positions, the lowermost showing it gorged with food. 2. The long-armed hydra, (hydra fusca.) Both species are of the natural size. But you are, perhaps, tired with this long account of a minute creature, and wish to contemplate beings of other races, | in the habits of which you take more delight. See that little bird on the stone which juts out in the middle of the rapid stream. It is the water ouzle, or dipper, (cinclus aquaticus. Beckst.) Mark how it suddenly dips down its head, and jerks its short erect tail; there, it has plunged into the water, and disappeared; do not fear for its safety, it has again made its appearance, and is perched by the water side; it will soon dive again, if we do not disturb it. There flies its mate: be sure its nest is near, but unless we watch the pair to their home, we shall never find it. They are procuring food for their nestlings; this consists of the larvæ of aquatic insects and the fry of small fish, such as the minnow, and it is in quest of these that they plunge so frequently beneath the water. How the bird manages to keep itself submerged and proceed in its search of prey, is not very easily explained, but that it does so is undeniable. In the summer of 1839, I had an opportunity, as indeed I have had many times before, of narrowly watching the habits of these birds, which are common along the trout streams that run through the rock-belted and romantic dales of Derbyshire. Often and often have I watched them plunge in and reappear at a considerable distance, unwet, and then flit a few yards further, settle on a stone or crag, and again plunge and emerge as before; but whether they walk at the bottom deliberately, (an unlikely mode,) or proceed by the action of their wings, (an opinion to which I incline,) I never could positively determine; but where the water has been too shallow to cover them entirely, I have remarked their wings rapidly vibrating. The nest of these birds, composed externally of moss and green lichen, and lined with decayed leaves, is generally hidden in the fissure of some rocky bank overhanging the stream, or between the interstices of narrow stones. I observed one, in 1839, in the fissures beneath the rude stones of a small bridge across the Wye, near Buxton, and another in the ruins of an old water mill, among which the stream was dashing rapidly along. The eggs, five in number, are of a clear white: the young leave the nest before being able to fly with perfect facility, but even then, dive with great promptitude and apparent facility. There flits another tenant of the river, rapid and direct in its flight as an arrow, and glancing as it passes, like burnished metal in the sun. It is the kingfisher. (Alcedo ispida.) It is also a diver in pursuit of its prey, which consists almost exclusively of small fish, which it takes as they rise near the surface, darting impetuously upon them, and carrying them to some favourite perching place, then to be eaten or taken to its young. Having secured its prey, the kingfisher carries it to land, and kills it by beating it against a stone or the stump of a tree, on which it may rest, and then swallows it whole the bones and undigestible parts being rejected in the form of small pellets by the mouth, as is the case with the owl and other carnivorous birds. It rears its young in a deep hole, running diagonally upwards, and excavated in the soft steep bank of the river; sometimes it takes possession of the deserted burrow of a water-rat, enlarging it to suit its own convenience. It makes no nest, but the young are soon surrounded by the rejected pellets of fish-bones; they are very voracious, and their continual cry for food often leads to their discovery. As soon as fledged, they acquire the metallic brilliancy of their parents, a circumstance wisely ordained, for this burnished surface is requisite for enabling the plumage to throw off the water, so as to prevent it from becoming saturated by diving; and by this means alone can the young birds procure their own food, which they are thus enabled to do as soon as they can fairly fly. But let us now pass into the wood, for the day is beginning to be hot, and the leafy trees will form a pleasant shade. There goes the squirrel; how nimbly he ascends that smooth-barked beech; his mate is probably with her young in their nest; you may see it like that of a bird, in the fork of those tall branches, almost concealed by the foliage and thick boughs. The nest of the squirrel is very curious, and it is remarkable that it should so much resemble those of the feathered It is composed of fibres and twigs, curiously intertwined and lined with leaves and moss. The young are three or four in number, and remain associated with their parents till the following .spring, when they separate and choose their mates; the male and female remain attached and occupy the same tree for many seasons, having around it a little territory of their own, in which they seek their subsistence. race. Observe that pretty bird which is now so nimbly running round and up the trunk of the fine tree before us: few birds display more activity or address than bark-climbers; in this respect this bird even exceeds the woodpecker, as it is not only capable of ascending, but of descending also; its tail, however, is flexible, and never used as an assistant in climbing, as it is by the latter. The bird in question is the nuthatch (Sitta Europea.) The nuthatch is not uncommon in old woods, throughout a great part of our island; but is not found either in Cornwall, or in the more northern districts of Scotland; it feeds upon such insects and their larvæ as frequent and injure the bark of trees, on which account_it deserves protection: but seeds, and the kernels of the filbert and hazel nuts, also form part of its diet, and hence it is capable of maintaining itself during the winter, partly by searching out the larvæ concealed in the crevices of the bark, and partly by the wild fruits mentioned. The method of arriving at the kernel of the hazel nut, or filbert, is very ingenious, if such a word be permitted, as applicable to the directions of instinct. It first detaches the nut from the husk, or envelope, by means of its bill; it then fixes it firmly in the crevice or chink of a tree, and hammers it with its bill, repeating its strokes until the shell is broken: a convenient place for this purpose is generally resorted to time after time; a hoard of refuse nut shells accumulating in the cavity or spot where the operation is carried on. The nuthatch breeds in the holes of trees, often appropriating the deserted habitation of a woodpecker; and when the orifice is larger than necessary, it narrows the entrance with mud or clay, and gravel, mixed together, and plastered on the margin of the opening, very neatly, so as to form a barricade, leaving an aperture just sufficient for its own ingress and egress. From this circumstance, has arisen one of its names among the French, that of mason woodpecker. The nest is composed of dried leaves, artlessly put together; the eggs are five in number, greyish-white, spotted with reddishbrown. The female sits very close, and is resolute in the defence of her nest, hissing like a snake, and striking violently with her bill. The call note of the nuthatch in spring is a loud, shrill whistle. There is another little bird, creeping mouse-like around the bark of that tree, which it so closely resembles s in the brown colour of its plumage, that did not its movements betray it, it might easily be passed by unnoticed. It is termed the creeper (Certhia familiaris) from its actions, and may be approached very nearly; watch it, see how it ascends, winding spirally round the trunk; it cannot descend like the nuthatch, and therefore generally begins its travels up the tree, in quest of insects, from the lower part of the trunk, using its stiff, pointed, and deflected tail as a support |