CLASS IV—BATRACHIA.
The Batrachia. Class IV of the Vertebrata comprises the Batrachia. Batrachia, which are divided into three orders: I Pseudophidia, II Urodela, III Anura. The first order comprises the limbless worm-like reptiles of the genus Cæcilia of Africa and South America; the second includes the Newts, the Salamanders, etc., etc.; the third the Frogs and the Toads. Leaving the first two orders, we devote a few lines to the third, dealing with the Toad, the Common Frog and the Tree Frog. The members of this order are singular for the extraordinary changes through which they pass between birth and maturity. As Tadpoles, in which form they first reach life, they have thick black legless bodies ending in tapering tails, and are provided with the fishlike anatomy necessary to an aquatic existence. In the process of development they completely change both in internal arrangement and external appearance. The gills are exchanged for lungs, the legs supersede the tail and the internal system undergoes corresponding change. In the end the animal becomes semi-aquatic, capable of living under water for some time, but compelled to come to the surface for air at intervals; and also of living out of the water altogether in such places as afford sufficient moisture, damp being as necessary to their comfort as food and air. They hybernate in the winter and propagate in the spring; and in times of drought burrow into the earth and remain lethargic until rain falls. They feed on insects and slugs for which they have a voracious appetite. Their tongues, which like those of the chameleon and other insect eaters, are furnished with a sticky mucus to which insects adhere,—when in repose, turn inwards towards the throat, and the act of catching flies and other insects is simply that of flapping the tongue out and in again, an act performed with such rapidity as to almost escape observation.
The Common Toad. The toad is found in all temperate and torrid climes. It hides in damp secluded places during the day emerging in search of food at night, or after the fall of rain. Though voracious in its appetite, it can accommodate itself to circumstances, and can subsist with little food, if its abode be damp. Failing food and damp, it has yet another resource, namely that of sleep, or torpor, in which condition it can lay by and wait for better times. Under such circumstances, the toad naturally lives a long life, and survives conditions usually fatal. The voracity of the toad is attested by the following incident, furnished by Captain Brown. "A gentleman who resides at Keswick, Cumberland, one evening in the latter end of July, observed a rustling among the strawberries in his garden, and on examining what it was, found that a toad had just seized a field-mouse, which had got on the toad's back, scratching and biting to get released, but in vain. The toad kept his hold, and as the strength of the mouse failed, he gradually drew the unfortunate little animal into his mouth, and gorged him."
Tame Toads. The toad may be easily tamed. Mr. Wood tells of one which lived with a family for years and was in the habit of supping on a piece of sugar. The story of the Duke of Wellington and the tame toad deserves telling in this connection. The Duke of Wellington was one day taking his usual country walk, when he heard a cry of distress. He walked to the spot, and found a chubby, rosyfaced boy lying on the ground, and bending his head over a tame toad, and crying as if his little heart would break. Enquiry elicited the fact that the boy was about to be sent to boarding school and that he was afraid the toad, lacking his attention, would die in his absence. The duke promised to look after the toad, and apprise the boy, from time to time, of its condition. During the time the boy was at school he received five letters couched in the following terms:—Strathfieldsaye, July 27, 1837. "Field Marshal the Duke of Wellington is happy to inform William Harries that his toad is alive and well." When the boy returned for his Christmas holidays, the toad was, as the duke said, "Alive and well," but, in accordance with the usual habits of these animals, he was in his winter's sleep, in which he remained until spring and genial weather brought him from his well-guarded hole in the ground.
The Common Frog. The Common Frog (Rana Temporaria) is now found all over the British Isles. Formerly unknown in Ireland it was introduced there about the year 1700 and has since spread all over the country. The frog is more sociable than the toad, and is often seen, and heard in large numbers; his habits, however, are very similar, and his mode of seizing his prey the same. The Edible Frog belongs to Europe, where it is used as an article of food, and is not found in England. The Bull Frog is an Indian Variety and attains to a great size. The American Bull Frog is also an interesting species.
The Ingenuity of the Frog. Mr. Jesse gives the following illustration of the ingenuity of the Frog: "I may mention a curious observation made in regard to some frogs that had fallen down a small area, which gave light to one of the windows of my house. The top of the area being on a level with the ground, was covered with some iron bars, through which the frogs fell. During dry and warm weather, when they could not absorb much moisture, I observed them to appear almost torpid; but when it rained they became impatient of their confinement, and endeavoured to make their escape, which they did in the following manner. The wall of the area was about five feet in height, and plastered and whitewashed, as smooth as the ceiling of a room. Upon this surface the frogs soon found that their claws would render them little or no assistance; they therefore contracted their large feet, so as to make a hollow in the centre, and by means of the moisture which they had imbibed in consequence of the rain, they contrived to produce a vacuum, so that by the pressure of the air on the extended feet (in the same way that we see boys take up a stone by means of a piece of wet leather fastened to a string), they ascended the wall and made their escape. This happened constantly in the course of three years."
The Tree Frog. The Tree Frog, of which there are numerous varieties, belongs to both East and West occurring in China and Japan or well as in North and South America. It is not found in England. Mr. Gosse says: "They are very numerous in the damp woods of tropical America, and reside by day in the tufts of those parasitical plants, which form reservoirs for rain-water. The under-surface of their bodies is very different to that of the terrestrial species; for the skin, instead of being smooth, is covered with granular glands, pierced by numerous pores, through which the dew or rain, spread on the surface of the leaves, is rapidly absorbed into the system, and reserved to supply the moisture needful for cutaneous respiration. The males make the woods resound throughout the night with their various cries, and, mingled with the shrill chirping of insects, quite banish sleep from the stranger's eyes."