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 with. out 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 of ten or twelve.

the

age

The full-grown animals have four feet, and their

is not covered with either plates or scales, but

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

* SYNONYMS.-Rana temporaria. La Rousse, la Muette.-La Cepede.-Shaw's Gen, Zool. vol. 3. tab. 39.

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 pleasure 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 aniniature. 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 hav ing 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

to the fore-part of the mouth, so that, when unem ployed, it lies with the tip towards the throat. The animal by this singular contrivance is enabled to bend it to a considerable distance out of its mouth. When it is about to seize on any object, it darts it out with great agility, and the prey is secured on its broad and jagged glutinous extremity. This it swallows with so instantaneous a motion that the eye can scarcely follow it".

Nothing can appear more awkward and ludicrous than a Frog engaged with a large Worm or a small snake; for nature seems to have put a restraint upon the voracity of these animals, by form. ing them very unaptly for seizing and holding their larger prey. Dr. Townson had a large Frog that one day swallowed in his presence a blind wormt near a span long, which in its struggles frequently got half its body out again: when completely swallowed, its contortions were very visible in the flaccid sides of its victor‡.

With respect to the popular superstition that Frogs frequently descend from the clouds, Mr. Ray informs us that, as he was riding one afternoon in Berkshire, he was much surprised at seeing an immense multitude of Frogs crossing the road. On further examination he found two or three acres of ground nearly covered with them; they were all proceeding in the same direction, towards some woods and ditches that were before them. He

* Shaw's Gen. Zool. iii. 97.

Anguis fragilis of Linnæus.

Townson's Tracts.

however traced them back to the side of a very large pond, which in spawning-time he was informed always abounded so much with Frogs that their croaking was frequently heard to a great distance; and he therefore naturally concluded that instead of being precipitated from the clouds, they had been bred there, and had been invited by a refreshing shower, which had just before fallen, to go out either in pursuit of food or of a more convenient habitation*.

Frogs are numerous in the parts of America, about Hudson's Bay, as far north as latitude 61°. They frequent there the margins of lakes, ponds, rivers, and swamps; and as the winter approaches, they burrow under the moss, at a considerable distance from the water, where they remain in a frozen state till spring. Mr. Hearne says, he has frequently seen them dug up with the moss frozen as hard as ice. In this state their legs are as easily broken off as the stem of a tobacco-pipe, without giving them the least sensation but by wrapping them up in warm skins, and exposing them to a slow fire, they soon come to life, and the mutilated animals gain their usual activity: if, however, they are permitted to freeze again, they are past all recovery.

The mode of respiration in these animals, in common with many of the other reptiles, is exceedingly curious. The organs adapted to this use are not placed in the belly, nor in the lungs themselves,

* Ray's Wonders of the Creation, 163.

+ Hearne, 397.