Hylaplesia Tinctoria
(A frog-like toad of tropical America)
“And there is a still further difference: the tadpole lives exclusively on vegetable matter, its mouth is equipped with a sort of small horny beak to browse the foliage of water-plants, and in its big belly it has a very long intestine coiled about several times so as to prolong the passage of the food through the body and thus make sure that all the juices it may contain are extracted. The mature batrachian exchanges this horny beak for real jaws furnished with irregularities that serve as teeth, it [[276]]lives solely on an animal diet, especially on insects, and its intestine is short because the food it eats is easy of digestion and readily yields what nourishment it contains.
“To turn a tadpole into a frog or a toad it is not enough to change its respiratory and digestive organs; new organs form, organs of which there was not the least sign when the creature was hatched, while still others disappear without leaving any trace. The tadpole is born absolutely without legs. After a while the hind legs appear, later come the fore legs, and still later the tail shrinks and vanishes.”
“I remember seeing tadpoles,” said Jules, “some with two legs, some with four; but every one of them had a tail.”
“When the tail has disappeared the animal is no longer a tadpole, but a young toad or frog.”
“Does the tail come off itself, or does the animal pull it off?” Emile inquired with eager interest.
“Neither the one nor the other. The tail is too valuable when the change takes place to be thrown away in that reckless fashion. It contains a store of material suitable for making something else in the bodily organism. When the legs begin to put forth, when the organs of digestion and those of respiration begin to take a new form, these new creations, these transformations, require material with which to build. Fleshy substance is needed for the up-building of the body just as bricks and mortar are needed for the construction of the house. Of course [[277]]the tadpole eats to make flesh and to provide a reserve for the work of transformation; but this method of accumulation is slow, and therefore, to save time, the organs useless to the future animal are destroyed, bit by bit, and their material is used in the construction of new parts. It is thus that the tail disappears. The blood circulating through it gradually eats it away, dissolves it, as we might say, at the proper time and carries elsewhere the fluid substance, which, turned again into flesh, helps to form the legs or other parts of the remodeled organism.”
“What a deal of economy in getting rid of a tadpole’s tail!” exclaimed Emile. “Not a particle of it, even if no bigger than a pin’s head, must be thrown away, for it might be used to make the little toe on one of the feet.”