BUILDERS IN THE SAND. 17 



recovering from its fright, once more spreads its gill- 

 plumes abroad in the pellucid pool. 



The worm-architects teach us a lesson in " habit" 

 as applied to living nature. Each species adheres to 

 its own way of life and materials the Terebella to 

 its shells and particles ; the Sabella to its sand alone ; 

 and the Serpula to its limy investment. There is 

 " more than meets the eye " in these persistent and 

 regular building habits more, perchance, than the 

 mind can explain as things are. But at least we 

 may discover that what we call " habit " in anything, 

 is but a name for the regular repetition of ways, 

 tendencies, and methods, which, at first of chance 

 character, have become stereotyped to form the fixed 

 history of living things. 



