CHAPTER VII 



CRUSTACEANS 

 Crawfish 



Suggestions. — In regions where crawfish are not found, a live 

 crab may be used. Locomotion and behavior may be studied by 

 providing a tub of water, or better, a large glass jar such as a 

 broad candy jar. For suggestions on study of internal structure, 

 see p. 58. 



Habitat. — Do you often see crawfish, or crayfish, mov- 

 ing about, even in water where they are known to be abun- 

 dant? What does your answer suggest as to the time 

 when they are probably most active ? 



Why do you never see one building its chimney, even 

 where crawfish holes are abundant? Is the chimney 

 always of the same color as the surface soil? Are the 

 crawfish holes only of use for protection ? In what kind 

 of spots are crawfish holes always dug ? Why ? What 

 becomes of crawfish when the pond or creek dries up ? 

 How deep are the holes ? How large are the lumps of 

 mud of which the chimney is built? How does it get 

 them out of the hole ? Why is the mud built into a chim- 

 ney instead of thrown away ? (What would happen to a 

 well with its mouth no higher than the ground?) Why 

 are crawfish scarce in rocky regions, as New England ? 



How does the color of the crawfish compare with its 

 surroundings ? Is its color suited to life in clear or muddy 

 water ? Define protective coloration. 



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