These tadpoles are so perfectly unlike the animals in their complete state, that a person not conversant in natural history would hardly suppose them to bear any relationship to the frog; since, on a general view, they appear to consist merely of head and tail. Their motions are extremely lively, and they are often seen in such vast numbers as to blacken the whole water with their legions. They live on the leaves of duckweed and other small water-plants, as well as on various kinds of animalcules, &c. and when arrived at a larger size, they may even be heard to gnaw the edges of the leaves on which they feed, their mouths being furnished with extremely minute teeth or denticulations. The tadpole is also furnished with a small kind of tubular sphincter or sucker, beneath the lower jaw, by the help of which it hangs at pleasure to the under surface of the aquatic plants, &c. From this part it also occasionally hangs, when very young, by a thread of gluten, which it seems to manage in the same manner as some of the smaller slugs have been observed to practise. Its interior organs differ, if closely inspected, from those of the future frog, in many respects; the intestines in particular are always coiled into a flat spiral, in the manner of a cable in miniature.

When the tadpoles have arrived at the age of about five or six weeks, the hind legs make their appearance, gradually increasing in length and size; and, in about a fortnight afterwards, or sometimes later, are succeeded by the fore legs, which are indeed formed beneath the skin much sooner, and are occasionally protruded, and again retracted by the animal, through a small foramen on each side of the breast, and are not completely stretched forth till the time just mentioned. The animal now bears a kind of ambiguous appearance, partaking of the form of a frog and a lizard. The tail at this period begins to decrease, at first very gradually, and at length so rapidly as to become quite obliterated in the space of a day or two afterwards. The animal now ventures upon land, and is seen wandering about the brinks of its parent waters, and sometimes in such multitudes as to cover a space of many yards in extent. This is the phenomenon which has so frequently embarrassed the minds not only of the vulgar, but even of some superior characters in the philosophic world; who, unable to account for the legions of these animals with which the ground is occasionally

the popular belief of their having descended from the clouds in showers.

As soon as the frog has thus assumed its perfect form, it feeds no longer on vegetables, but on animal food; supporting itself on small snails, worms, &c. and insects. For the readier obtaining its prey, the structure of its tongue is extremely well calculated, being so situated that the root is attached to the fore rather than the hind part of the mouth; and when at rest, lies backwards, as if the ani. mal was swallowing the tip. By this means the creature is enabled to throw it out to some distance from the mouth, which is done with great celerity, and the bifid and glutinous extremity secures prey, which is swallowed with an instantaneous motion, so quick that the eye can scarcely follow it.

the

The frog can hardly be said to arrive at its full size till the age of about five years, and is supposed to live at least twelve or fifteen years.

The frog is extremely tenacious of life, and, like other amphibia, will survive for a considerable space the loss of many of its organs. If confined entirely under water, it is still enabled to support its existence for several days, as appears by Sir Thomas Brown's experiment, who kept a frog under water six days. On the contrary, it cannot so well dispense with the want of water, and is unable to survive too long an exposure to a dry air and a hot sun. It is, therefore, particularly careful to secure a retreat where it may en. joy the benefit of shade and a sufficient supply of moisture. It delights, however, to bask occasionally in a moderate sunshine, and is unable to support severe cold.

Tree.Frog.

Rana arborea.-LINN.

In the beauty of its colours, as well as in the elegance of its form, and the agility of its movements, the tree-frog exceeds every other European species. It is a native of France, Germany, Italy, and many other European regions, but is not found in the British islands. Its principal residence, during the summer months, is on the upper parts of trees, where it wanders among the foliage in quest of insects, which it catches with extreme celerity, stealing

softly towards its prey in the manner of a cat towards a mouse, and when at the proper distance, seizing it with a sudden spring, frequently of more than a foot in height. It often suspends itself to the under parts of the leaves, thus continuing concealed beneath their shade. Its size is smaller than any other European frog, except the fire-frog. Its colour on the upper parts is green, more or less bright in different individuals; the abdomen is whitish, and marked by numerous granules; the under surface of the limbs is reddish, and the body marked on each side by a longitudinal blackish or violet-coloured streak. The body is smooth above, and moderately short; the hind legs are very long and slender; the fore feet have four and the hind feet five toes, all of which terminate in rounded, flat, and dilated tips, the under surface of which, being soft and glutenous, enables the animal to hang with perfect security from the leaves of trees, &c. The skin of the abdomen is also admirably calculated by nature for this peculiar power of adhesion, being covered with small glandular granules, in such a manner as to fasten closely even to the most polished surface; and the animal can adhere at pleasure to that of glass, in whatever position or inclination it is placed, by merely pressing itself against it.

Though the tree-frog inhabits the woods, during the summer months, yet on the approach of winter it retires to the waters, and there submerging itself in the soft mud, or concealing itself beneath the banks, remains in a state of torpidity, and again emerges in the spring, at which period it deposits its spawn in the waters, like the rest of this genus. During their residence among the trees, they are observed to be particularly noisy on the approach of rain; so that they may be considered, in some measure, as a kind of living barometers; more especially the males, which, if kept in glasses, and supplied with proper food, will afford an infallible presage of the changes of the weather.

3. Toad.

Rana bufo.-LINN.

Of all the European toads, this seems to be the most universally known; at least, in its complete or perfect form. It is found in gardens, woods, and fields; and frequently makes its way into cel. lars, or any obscure recesses in which it may occasionally conceal itself, and where it may find a supply of food, or a security from

too great a degree of cold. In the early part of spring, like others of this genus, it retires to the waters, where it continues during the breeding-season, and deposits its ova or spawn in the form of double necklace-like chains or strings of beautifully transparent gluten, and of the length of three or four feet.

The toad is an animal too well known to require any very parti• cular description of its form. It may be necessary to observe that it is always covered by tubercles, or elevations on the skin, of larger or smaller size in different individuals; and that the general colour of the animal is an obscure brown above, much paler and irregularly spotted beneath.

The toad arrives at a considerable age; its general term of life being supposed to extend to fifteen or even twenty years: and Mr. Pennant, in his British Zoology, gives us a curious account, communicated by a Mr. Arscott, of Tehott, in Devonshire, of a toad's hav ing lived, in a kind of domestic state, for the space of more than forty years, and of having been in a great degree tamed, or reclaimed from its natural shyness or desire of concealment; since it would always regularly come out of its hole at the approach of its master, &c. in order to be fed. It grew to a very large size, and was considered as so singular a curiosity, that even ladies, laying aside their usual aversion and prejudices, requested to see the favourite toad. It was, therefore, often brought to table, and fed with various insects, which it seized with great celerity, and without seeming to be embarrassed by the presence of company. This extraordinary animal generally resided in a hole beneath the steps of the house door, fronting the garden; and might, probably, have survived many years longer, had it not been severely wounded by a raven, which seized it before it could take refuge in its hole; and notwithstanding it was liberated from its captor, it never again enjoyed its usual health, though it continued to live above a year after the accident happened.

With respect to the supposed venomous qualities of the toad, from the experiments of Laurenti, it appears that small lizards, on biting the common toad, were for some time disordered and paralytic, and even appeared to be dead, but in a few hours were completely recovered.

It is also observed, that dogs, on seizing a toad, and carrying it for some little time in their mouth, will appear to be affected with a very slight swelling of the lips, accompanied by an increased eva

cuation of saliva; the mere effect of the slightly acrimonious fluid which the toad, on irritation, exsudes from the skin, and which seems, in this country at least, to produce no dangerous symptoms in such animals as happen to taste or swallow it. The limpid fluid also, which this animal discharges when disturbed, is a mere watery liquor, perfectly free from any acrimonious or noxious qualities, and appearing to be no other than the contents of a peculiar reservoir, common to this tribe, destined for some purpose in the economy of the animals which does not yet appear to be clearly understood. The common toad may therefore be pronounced innoxious, or perfectly free from any poisonous properties, at least with respect to any of the larger animals; and the innumerable tales recited by the older writers of its supposed venom, appear to be either gross exaggerations, or else to have related to the effects of some other species mistaken for the common toad; it being certain that some of this genus exsude from their skin a highly acrimonious fluid.

It might seem unpardonable to conclude the history of this animai, without mentioning the very extraordinary circumstance of its having been occasionally discovered enclosed or imbedded, without any visible outlet, or even any passage for air, in the substance of wood, and even in that of stone or blocks of marble.

On this subject a curious experiment was made by Mons. Herris. sant, of the French Academy, in consequence of an assertion, that in the year 1771, on pulling down a wall at a seat belonging to the Duke of Orleans, and which had been built forty years, a living toad had been found in it; its hind feet being confined or imbedded in the mortar. M. Herrissant therefore, in the presence of the academy, inclosed three toads in as many boxes, which were imme diately covered with a thick coat of plaster or mortar, and kept in the apartments of the academy. On opening these boxes eighteen months afterwards, two of the toads were found still living: these were immediately re-inclosed; but on being again opened some months after, were found dead. These experiments are, perhaps, not very conclusive; and only appear to prove what was before well known, viz. that the toad, like many other amphibia, can support a long abstinence, and requires but a small quantity of air: but in the accounts generally given of toads discovered in stones, wood, &c. the animals are said to have been completely impacted or imbedded, and without any space for air.

[Herrissant. Mem. de l'Acad. Royal. Shaw.