PREFACE 



IT was suggested to me that I should try to prepare 

 this account of our food mollusks for three groups of per- 

 sons, namely, those who eat them, those who may be or 

 desire to become directly interested in their culture, and 

 those who may have an interest in the biological problems 

 involved in their artificial control. This suggestion I 

 adopted, and many times since have wondered at the reck- 

 lessness of my courage in attempting a performance of so 

 varied a character. I recall vividly the impression made 

 on my youthful mind years ago on witnessing the evolu- 

 tions of three beautifully matched horses and the graceful 

 feat of James Robinson in riding them around a ring. 

 Though in my wildest childhood imaginings I never 

 dreamed of attempting or desired to attempt so skilful 

 an act, I have in the last months, at a period of life that 

 should conventionally be characterized at least by sedate- 

 ness, experienced the disquieting sensation of having actu- 

 ally attempted much the same kind of a performance in 

 thus endeavoring to present several topics that might hold 

 the attention of readers possessing widely different in- 

 terests. While desiring to exhibit these subjects so as to 

 bring out their most interesting features, I, of course, 

 have been compelled to present them for brief intervals 

 one at a time, thus always giving two-thirds of my 

 readers an opportunity to yawn. If, however, it should 

 happen that the other third is interested, I shall be amply 

 paid for my effort. 



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