and swallow them, lanterns, head-light and all! And so, with all this eating and chasing and fighting and fleeing and hiding and lurking, it comes about that wherever there is decent water on land or sea there are fishes to match it. And every part of every fish is made expressly for the life the fish has to lead. If any kind failed to meet requirements, other fishes would devour and destroy it. So only the fit can survive and these people the water after their kind. All kinds of fishes are good to eat except a few which are too tough, a few which are bitter, and a few that feed on poisonous things about the coral reefs and so become poisonous themselves. Some are insipid, some full of small bones and some are too lean or too small to tempt anybody, unless it be another fish. But this is their business, not ours, and they have flesh enough for the things they have to do. The biggest fish is the great basking shark, which grows to be thirty-five feet long, and lies on the surface of the sea, like a huge saw-log, filling its great mouth with the little things that float along beside it. The smallest of all fishes lives in the everglades of Florida and the streams that run out of them. You can find them in the little brook that runs through Jacksonville. I have netted them there with a spread umbrella, which will serve when you cannot get a better dip-net. They are prettily barred with jet black on a greenish ground, and they belong to that group of top minnows to which Agassiz gave the name of _heterandria_. It is hard to say what is the highest fish--what is the one which has undergone the greatest modification of structure. Perhaps this place should be assigned to the sole, with its two eyes both on one side of the head, peering through the same socket, while the socket on the other side has no eye at all. Or perhaps we may place as highest some specialized form as the angler or the sargassum fish, which has the paired fins greatly developed almost like arms and legs, and which has a dorsal spine modified into a fishing rod, which has a bait at the end, hanging over the capacious mouth.