THE SHELL BOOK 



CHAPTER I: HOW TO KNOW SHELLS 



All up and down the ocean border, east and west and south, 

 I have met people picking up shells. Children and grown people 

 both give themselves to the eager search for ocean treasures left 

 by the outgoing tide. The fascination of the pursuit — ^who has 

 not yielded to it ? Who ever came back from a walk on the beach 

 without at least a handful of shells too irresistibly pretty or 

 interesting to leave ? 



Ask the name of a shell and the reply is almost invariably: 

 " It's some kind of clam," or, " It's some kind of snail." Few 

 grown people regard with any feeling but distaste, if not disgust, 

 "the slimy thing inside." Apparently they distrust the state- 

 ment that the shell is but the skeleton of the living mollusk 

 it protects. 



It is not surprising that a popular misconception exists as to 

 the origin of shells. Even scientists devoted to conchology used 

 to discard the soft parts without considering their structure. 

 The shell was the thing. On its characters alone classification 

 was based. Now the whole mollusk is the thing, shell and all. 

 The name is from the Latin adjective mollis, which means soft. 

 Some mollusks have no shells at all. Most of them have shells 

 for protection of their soft bodies, but they do not build them, as 

 bees make comb of wax and the white-faced hornet builds her 

 paper palace. Mollusks are shell-builders in the same sense that 

 you and I are bone-builders. The fleshy mantle of the mollusk 

 secretes lime from the water and adds it, layer by layer, to the 

 growing shell. The horny skin outside and the pearly or enamel 

 lining protect the shell substance from the corrosive action of 

 acids in the water. 



When we consider how little was known a hundred years ago 

 about plants and animals compared with what the century has 



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