252 



NATURE-STUDY 



merets and the tail. What does the crayfish do with its 

 claws? How does it crawl? Observe the way it swims. 

 Note the hard shell. Crayfish grow by moulting their shells 

 like insects. We often find the little shafts or tunnels of 

 crayfish in wet meadows. They make these in digging 

 down for water or wet soil. Along rivers that are enclosed 



by dikes or levees, 



crayfish sometimes 

 cause great harm by 

 boring through the 

 earth wall and thus 

 beginning a great 

 crevasse or break 

 that may cause much 

 damage. Crayfish 

 are scavengers and 

 live upon dead ani- 

 mals, fish, etc. The protective coloration of the crayfish 

 should be referred to. Correct the misuse of the word 

 "crab" for crayfish. 



The Lobster and the Crab should be compared with the 

 crayfish as to structure. They are salt-water animals, and 

 are best studied at the seashore, where their life habits can 

 be observed. Lobsters are very much like large crayfish in 

 structure. Those seen in the markets are generally red, 

 but this is not their natural color, which is much like that of 

 the crayfish. The redness is due to the fact that the lob- 

 ster has been boiled. Crabs differ very greatly from the 

 crayfish in shape, and yet their relationship can be readily 

 recognized. Their bodies are short and broad, and their 

 abdomen is always bent under the thorax. They crawl 



FIG. 95. A Crayfish. 



