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138 See that little northeast room of the crawfish's stomach? It is not quite shut off from the main living-room. In that room are his stomach teeth. He has to have teeth to grind with, just as a hen does. But the hen, poor thing, has to use false teeth. You have seen her picking them up around the yard—little stones and bits of shell and such things, that she swallows.

The crawfish and his kind have three of these teeth in their stomachs. With these teeth they grind finer the food that they have first torn to pieces with their pincher claws.

The underside of a crawfish, showing the eyes, two long feelers, the large two-claw feet, four pairs of legs, and the tail with its fringe of little hairy feelers.

The crawfish seems to have started, as a baby, to divide his stomach into three rooms. When he gets to be a bossy cow, eating clover in the pasture, he really does divide it into four stomachs, as you know. The cow stops the food that needs the most digestion in the first stomach. The food that needs less grinding stops in the second stomach. Real fine, partly digested food, like bran-mash, goes straight through, "by express," into the third stomach. All of the food finally goes into the fourth and last stomach. The first stomach rolls the coarser food into little balls. These the cow brings up into her mouth again, and chews them over. Haven't you seen cows chewing their cuds?

In the crawfish there is a big front stomach, you see, like the first stomach of the cow, that we call the paunch. In the chicken it is the crop. Next comes the grinding mill in the northeast room, which works like the chicken's gizzard. Beyond this is the back room stomach that opens into the long, worm-like hallway that runs clear down to the tail.

This back stomach of the crawfish is lined with little things sticking out from its walls. These hold back all the food that is too large to go through. Without this "strainer," pieces of undigested food would get into Mr. Crawfish's little insides, and make him double