The upper part of the body is of a beautiful green, the lower part, where little tuberculi are visible, is white. A yellow line, lightly bordered with violet, extends on each side of the head and back, from the muzzle to the hind legs. A similar line runs from the jaw to the front legs. The head is short, the mouth round, and the eyes raised. Much smaller than the ordinary Frog, they are far more graceful. During the summer they live upon the leaves of trees in damp woods, and pass the winter at the bottom of some pond, which they do not leave till the month of May, after having deposited their eggs. They feed on small insects, worms, and mollusks; and in order to catch them, they will remain in the same place an entire day. During the glare of the sun, they remain hidden amongst the leaves; but when twilight approaches, they move about and climb up the trees. We must repeat of these Green Tree Frogs what we have already said of Frogs. Get rid of all prejudice towards their kind, and then you will examine with pleasure their lively colours, which harmonize so well with the green leaves; remark their tricks and ambuscades; follow them in their little hunting excursions; see them suspended upside down upon the leaves in a manner which appears marvellous to those who are not aware of the organs which have been given to enable them to attach themselves to the smoothest bodies: and it will give as much pleasure as can be derived from the consideration of the plumage, habits, and flight of birds. The croak of the Green Tree Frogs is like that of other Frogs, although less sharp and sometimes stronger in the males; it can be pretty well translated by the syllables caraccarac, pronounced from the throat. This cry is principally heard in the morning and evening; then, when one Frog begins to utter its croak, all the others imitate it. In the quiet night the voice of a troop of these little Batrachians sometimes reaches to an enormous distance.
Toads, Bufo, are squat and disagreeable in shape: it is difficult to comprehend why nature, which has bestowed elegance and a kind of grace upon Frogs and Tree Frogs, has stamped the Toad with so repulsive a form. These much despised beings occupy a large place in the order of nature: they are distributed with profusion, but one cannot say exactly to what end; their movements are heavy and sluggish. In colour they are usually of a livid grey, spotted with brown and yellow, and disfigured by a number of pustules or warts. A thick and hard skin covers a flat back; its large belly always appears to be swollen; the head a little broader than the rest of its body; the mouth and the eyes are large and prominent. It lives chiefly at the bottom of ditches, especially those where stagnant and corrupt water has lain a long time. It is found in dung heaps, caves, and in dark and damp parts of woods. One has often been disagreeably surprised on raising some great stone to discover a Toad cowering against the earth, frightful to see, but timorous, seeking to avoid the notice of strangers. It is in these different obscure and sometimes fœtid places of refuge that the Toad shuts itself up during the day; going out in the evening, when our common species moves by slight hops; whilst another, the Natterjack Toad, Bufo calamita, only crawls, though somewhat fastly. When seized, it voids into the hand a quantity of limpid water imbibed through the pores of its skin; but if more irritated, a milky and venemous humour issues from the glands of its back.
Fig. 7.—The Common Toad (Bufo vulgaris).
One peculiarity of its structure offers a defence from outward attacks. Its very extensible skin adheres feebly to the muscles, and at the will of the animal a large quantity of air enters between this integument and the flesh, which distends the body, and fills the vacant space with an elastic bed of gas, by means of which it is less sensible to blows. Toads feed upon insects, worms, and small mollusks. In fine evenings, at certain seasons especially, they may be heard uttering a plaintive monotonous sound. They assemble in ponds, or even in simple puddles of water, where they breed and deposit their eggs. When hatched, the young Toads go through the same metamorphosis as do the tadpoles of the Frogs.
Their simple lives, though very inactive, are nevertheless very enduring; they respire little, are susceptible of hibernation, and can remain for a considerable time shut up in a very confined place.
It is proper, however, to caution the reader against believing all that has been written about the longevity of Toads. Neither must implicit faith be given to the discovery of the living animal ([Fig. 7]) in the centre of stones. "That Toads, Frogs, and Newts, occasionally issue from stones broken in a quarry or in sinking wells, and even from coal-strata at the bottom of a mine," is true enough; but, as Dr. Buckland observes, "the evidence is never perfect to show that these Amphibians were entirely enclosed in a solid rock; no examination is made until the creature is discovered by the breaking of the mass in which it was contained, and then it is too late to ascertain whether there was any hole or crevice by which it might have entered." These considerations led Dr. Buckland to undertake certain experiments to test the fact. He caused blocks of coarse oölitic limestone and sandstone to be prepared with cells of various sizes, in which he enclosed Toads of different ages. The small Toads enclosed in the sandstone were found to die at the end of thirteen months; the same fate befell the larger ones during the second year: they were watched through the glass covers of their cells, and were never seen in a state of torpor, but at each successive examination they had become more meagre, until at last they were found dead. This was probably too severe a test for the poor creatures, the glass cover implying a degree of hardness and dryness not natural to half amphibious Toads. Moreover, it is certain that both Toads and Frogs possess a singular facility for concealing themselves in the smallest crevices of the earth, or in the smallest anfractuosities of stones placed in dark places.
This animal, so repulsive in form, has been furnished by nature with a most efficient defensive armature; namely, an acrid secretion which will be described farther on. It is a bad leaper, an obscure and solitary creature, which shuns the sight of man, as if it comprehended the blot it is on the fair face of creation. It is, nevertheless, susceptible of education, and has occasionally been tamed; but these occasions have been rare. Pennant, the zoologist, relates some curious details respecting a poor Toad, which took refuge under the staircase of a house. It was accustomed to come every evening into a dining-room near to the place of its retreat. When it saw the light it allowed itself to be placed on a table, where they gave it worms, wood-lice, and various insects. As no attempt was made to injure it, there were no signs of irritation when it was touched, and it soon became, from its gentleness (the gentleness of a Toad!), the object of general curiosity; even ladies stopped to see this strange animal. The poor Batrachian lived thus for six and thirty years; and it would probably have lived much longer had not a Crow, tamed, and, like it, a guest in the house, attacked him at the entrance of his hole, and put out one of his eyes. From that time he languished, and died at the end of a year.
Fig. 8.—Surinam Toad (Pipa monstrosa).