Nearly every pond, marsh, and slow stream abounds also in water-snakes, which are ugly in disposition as well as in color, and feed mainly on fishes, both dead and alive. Of this kind is the only snake to be found in England except the viper. Perhaps the most curious of the colubrine snakes is the egg-eating snake of South Africa. It is quite a small snake, not more than two feet long, and scarcely thicker in body than a man's little finger; yet it will swallow pigeons' eggs quite easily, and, if it is very hungry indeed, will dispose of a hen's egg! This, of course, is owing to the way in which the bones of the mouth are made. But if you were to watch one of these snakes as it was eating an egg, you would see a very strange thing happen. The egg would pass down the throat, and for a few inches you would be able to watch its outline as it moved along toward the stomach. Then, quite suddenly, the swelling would disappear! The fact is this. About thirty of the vertebræ have each a long, slender spine springing from the lower surface, and the tips of these spines pass through the upper part of the throat and project inside it, just like a row of little teeth in the wrong place. Just as the egg, while it is being swallowed, comes against these teeth, the snake contracts the muscles of its throat. The result is that the teeth pierce the egg from end to end and cut it in two. Then the contents flow onward down the throat, while the two halves of the shell, nearly always packed one inside the other, are shortly afterward spit out of the mouth. PYTHONS The pythons are very formidable snakes, not because they are venomous--for they have no poison-fangs--but owing to their immense size and strength. When fully grown they may measure as much as thirty feet in length, while their bodies are as big round as a man's thigh; and even when they are only half as long they are still most dangerous creatures, for they could crush a man to death in two or three minutes. When a python attacks, it seizes its victim with its jaws, flings its coils one over another around it, and then squeezes so hard that in a very few minutes the bones fly into splinters, and the body is reduced to pulp. And a large python can swallow a half-grown sheep or a good-sized dog without any difficulty at all. After the snake has swallowed its victim it becomes very drowsy, and often sleeps heavily for several days. Another very curious fact with regard to the python is that it actually hatches its eggs by the warmth of its own body. It first collects the eggs into a little pile, and then coils itself round them, after which it remains perfectly still for nearly two months. During the whole of that time its bodily heat is much greater than usual, and at last the egg-shells split, and out from each comes a baby python. A fortnight or so later they change their skins, and then are quite large and strong enough to kill and swallow small birds.