34 



THE YOUNG NATURALIST. 



eggs, each globe or egg having a black spot in the centre, from which the 

 tadpole or imperfect frog issues later on. Each female frog is said to pro- 

 duce from 900 to 1,000 eggs. These are first deposited at the bottom of the 

 pool, but in a short time expand and rise to the surface. In about three 

 weeks or a month's time the eggs begin to produce tadpoles, but in warmer 

 climates they are developed much sooner than this. The ovum (the black 

 speck in the centre of the globe), is round at first, but gradually becomes 

 elongated and soon assumes the shape of the tadpole, acquires life and motion, 

 and finally by wriggling, the young tadpole frees itself from its slimy surround- 

 ings. Thus about the second week in April we find the tadpole of the frog 

 in great plenty in our ponds and ditches. The tadpole presents the appear- 

 ance of a large head, a long thin tail, but no body or limbs. It is widely 

 distinct from the frog, breathing by means of hrancJiia, or gills like a fish, 

 while the frog is amphibious and provided with lungs. The frog-tadpole is 

 lighter in colour than that of the toad. Placed under a powerful microscope 

 it forms a very interesting object, the circulation of the blood being very 

 plainly to be seen. 



On its emergence from the egg the young " taddy " sets to work and eats 

 the collapsed remains of its former habitat, but as it increases in size it be- 

 comes more ambitious. It now devours the green film covering the surface 

 of the water, sucks the juices of any unfortunate rat, dead and floating on the 

 water, and worse than all becomes a cannibal, for if any of its smaller com- 

 panions become disabled they are quickly swallowed. This cannibalistic pro- 

 pensity exhibits itself principally at an advanced period of its growth. It will 

 also prey on the small tadpole of the newt or eft. It is very gregarious in 

 its habits, playing merrily in shoals like the minnows, and often collecting in 

 in large masses at the edge of the pool. In getting through the water the 

 little reptile seems to depend principally upon its tail, which it uses very 

 briskly. 



When the tadpole has attained a certain age a most important change takes 

 place in its form, for almost simultaneously a tiny leg gradually bulges out 

 on each side, just above the tail. A short time later the fore feet appear, 

 and the creature then resembles a small eft. Einally it undergoes another 

 change, its tail gradually disappears, and it is then a perfect little frog. 

 Once, however, in my rambles (August 18th, 1879), I met with a little frog 

 travelling along a road, which had not parted with the tail which it had worn 

 as a tadpole, though Master Erog himself was considerably more than an 

 inch long. Some companions of his, travelling the same road, though much 

 smaller, had got rid of their latter ends. Tadpoles may easily be kept by the 

 experimental young naturalist, in wide shallow vessels, with a layer of gravel 



