The season of tadpoles is not a season recognised by housekeepers and gourmets (except in France, where frogs are eaten in April), but one dear to schoolboys and all lovers of Nature. The ponds on heaths and in the corners of meadows now show great masses of soft jelly-like balls of the size of a marble, huddled together and marked each by a little black spot at its centre, as big as a rape-seed. This is the “spawn” of our common frog. The spawn of the common toad is very similar, but the black spots are set in long strings of jelly, not in separate balls. The little black body is precisely the same thing as the yellow part of a hen’s egg, and the jelly around it corresponds to the “white” of the bird’s egg; but there is nothing to represent the shell. The “yelk” of the bird’s egg is, it is true, much larger, but corresponds to the black sphere of the frog’s egg—the actual germ—and is like the latter a single protoplasmic cell, distended with nourishing granular matter. It is the excess of this matter which makes the yellow ball of the bird’s egg so much bigger than the black or rather deep-brown germ of the frog. The little black spheres elongate from day to day in the warm spring weather, and at last the minute tadpoles (see Fig. 43 and its explanation) break loose from the jelly, hanging on to its surface by aid of a tiny sucker, and feeding on the minute green vegetable growths which have appeared all over the jelly-like mass. Their rate of growth depends very much on the temperature, and is much more rapid in Italy and the South of France than in England. At first they are so small that it is difficult to distinguish, except with a pocket-lens, the little black plume-like gills on each side of the head, and it is only as they grow bigger and lose these little plumes that the young things assume the characteristic shape of a rounded head—really head and body—with a long flattened tail which strikes vigorously to the right and left, and enables the tadpole to swim like a fish. [Illustration: FIG. 43.—Stages in the growth from the egg of the common frog—drawn of the natural size. 1. Egg in its jelly-like envelope. 2. Very young tadpoles adhering to weed by their suckers (placed just below the mouth). 3. Very young tadpole, showing two pair of external gills: a third pair is present, but so small as to be invisible without magnification. 4, 5, 6. Stages in the later growth of the tadpole: the external gills have disappeared, but the legs have not yet made their appearance. 7. Tadpole of full size, with fore and hind legs. 8. The tadpole has now become a small frog, and has left the water. The tail has shrunk, but has not entirely disappeared: it remains throughout life hidden by the skin and the large thighs of the growing frog. This figure has been kindly supplied by Messrs. Macmillan & Co., from Dr. Gadow’s volume on the “Amphibia and Reptiles,” in the _Cambridge Natural History_.]