but particularly about the coasts of Italy and Sicily.

They are very strong and fierce, defending themselves with great vigour with their legs, and being able to divide very strong substances with their mouth. Aldrovandus assures us, that on offering a thick walking-stick to the gripe of one that he saw publicly exhibited at Bologna, the animal bit it in two in an instant*. -Their principal food is shell-fish, which their strong beak enables them to break from the rocks. But their voracity, it is said, even leads them to attack young Crocodiles, which they often mutilate of their limbs or tail. We are informed that, for this purpose, they frequently lurk in the bottom of Creeks along the shore, into which the Crocodiles sometimes retire backwards, because the length of their body prevents them from turning readily; and, taking advantage of this posture, the Loggerhead seizes them by the tail, having then nothing to fear from their formidable teeth†.

They range very far over the ocean. them was seen in latitude 30° north, sleeping on the surface of the water, apparently about midway between the Azores and the Bahama Islands, and these were the nearest possible land. This circumstance was the more remarkable as it happened in the month of April, just at their breeding time.

Rondeletius, who was a native of Languedoc, informs us, that he kept one of this species, which had been caught on the coast of Provence, for a considerable time. It emitted a confused kind of noise, and frequently sighed*.

Like the last species, they lay their eggs in the sand. Their flesh is coarse and rank; but their bodies afford a considerable quantity of oil, which may be used for various purposes, particularly for burning, or for dressing leather. The plates of the shell are not sufficiently thick to be of great use.

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The substance that we call Tortoise-shell is the production of the Imbricated Turtlet, a species considerably allied to the present, that is found in the Asiatic and American seas, and sometimes in the Mediterranean. The plates of this species are far more strong, thick, and clear, than in any other, and these constitute the sole value of the animal. They are semi-transparent, beautifully variegated with different colours, and, when properly prepared and polished, are used for a variety of ornamental purposes. They are first softened by steeping in boiling water, after which they may be moulded into almost any form.

THE FROG TRIBE.

THE animals that compose this tribe feed on insects and worms, residing principally on the ground, or partly in water, in dark and unfrequented places, from whence they crawl forth only in the night. Many of them have an aspect very disgusting and unpleasant. Some, however, less unpleasant to the sight, are furnished with slender limbs, and have their toes terminated by flat circularly expanded tips, which enable them to adhere at pleasure to the surfaces of even the smoothest bodies: these reside generally in the trees, where they adhere to the lower sides of the leaves or branches. None of them drink, but all the species absorb moisture through the skin.

They are all oviparous, and the eggs are perfectly gelatinous. From the egg proceeds a tadpole without feet, but furnished with a tail to aid its motion in the water: this drops off as the legs become protruded. In this imperfect state, the animals have also a sort of gills or subsidiary lungs; and several of them a small tube on the lower lip, by means of which they can fix themselves to bodies to eat, or perform other functions. They all arrive at maturity about their fourth year, and very few outlive the age of ten or twelve.

The full-grown animals have four feet, and their body is not covered with either plates or scales, but

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is entirely naked, They have a sternum or breastplate, but no ribs. They are destitute of tails, and their hind legs are longer than the others.

The number of species hitherto described is about fifty. These are divided into three sections: namely, Frogs, which have smooth bodies, longish legs, and discharge their eggs in a mass.

Hyle, or Tree Frogs, that have their hind legs very long, and the toes unconnected; and

Toads, which have their bodies puffed up and covered with warts. These have short legs, and do not leap. They discharge their eggs in a very long necklace-like string.

THE COMMON FROG*.

The Common Frog is found in great quantities in moist situations throughout Europe. Its colour is olive brown, variegated above with regular blackish spots. Beneath each eye there is a patch or mark that reaches to the setting-on of the fore-legs.

Its appearance is lively, and its form on the whole by no means inelegant. The limbs are well calculated for aiding the peculiar motions of the animal, and its webbed hind-feet assist its progress in the water, to which it occasionally retires during the heats of summer, and again in the frosts of winter. During the latter period, and till the return of warm weather, it lies in a state of torpor, either deeply plunged in the soft mud at the bottom

of stagnant waters, or in the hollows beneath their banks.

Its spawn, which is cast generally in the month of March, consists of a clustered mass of gelatinous transparent and spherical eggs, from six hundred to a thousand in number, in the middle of each of which is contained the embryo or tadpole, in the form of a black globule. The spawn lies a month or five weeks, according to the heat of the weather, before the larvæ or tadpoles are hatched.

The tadpole, as in several other species, is furnished with a kind of small tubular sucker beneath the lower jaw, by means of which it hangs at plea sure to the under surface of aquatic plants. The interior organs, when closely examined, are found to differ in many respects from those of the future Frog. The intestines, in particular, are coiled into a flat spiral form, somewhat resembling a cable in miniature. When the animal is about six weeks old, the hind-legs appear, and in about a fortnight these are succeeded by the fore-legs: in this state it seems to have alliance both to the Frog and Lizard. Not long afterwards the form is completed, and it, for the first time, ventures upon land. Frogs are at this period often seen wandering about the brinks of the water in such multitudes as to astonish mankind, and induce a belief, among the vulgar, of their having descended in showers from the clouds.

They now surrender their vegetable food for the smaller species of snails, worms, and insects; and the structure of their tongue is admirably adapted to seize and secure this prey: the root is attached