A MONOGRAPH OF THE AMERICAN SHIPWORMS. 



By Paul, Bartsch, 



Curator, Division of Mollusks, United States National Museum. 



INTRODUCTION. 



Shipworms, on account of their destriictiveness, have been objects 

 of inquiry ever since the clays of Theophrastus, Pliny, and Ovid. 

 When one follows the history of our knoAvledge of these mollusks, one 

 soon finds that the major output of literature dealing with this topic 

 is usually coincident with or immediately follows a destructive infes- 

 tation of these creatures. Literature produced at such times usually 

 deals with the more or less garbled rehash of past efforts, tinged with 

 enough local color to satisfy the popuhir needs of the moment. The 

 abatement of the disastrous plague is usually followed by a cessation 

 of scientific inquiry, and thus the world at large returns to placid 

 contentment and offers a prayer of thanksgiving for the lifting of the 

 scourge, hoping that the lightning will not strike on the same spot 

 a second time. We are altogether too prone to accept complacently 

 the constantly continued moderate (?) loss claimed by a persistent, 

 silent enemy. 



The perusal of the past literature has forced one question strongly 

 before me, and that is, why have not the various enlightened countries 

 depending more or less upon the sea, put forth a concerted inquiry 

 into the nature and life history of these pests, for these to-day are 

 scarcely known. Yes, I can say that the complete life history of not 

 a single species is known to-day. 



Most of the early authors seem to have contented themselves with 

 merely discussing the Teredo. Now, what do they mean by this? I 

 confess in most instances it is impossible to tell. Some of the bril- 

 liant work of the more recent cytologists and embryologists will be 

 properly referable only when future investigations of the same spe- 

 cies, carefully identified, will give a clue to the organism studied by 

 them. The statement that an earlier observer was in error when he 

 described such and such a structure, met in almost every treatise, ex- 

 presses plainly the fact that the two observers were not dealing with 

 the same species, and the error observed by number two in number 

 one's treatise reflects rather upon number two's limited knowledge 

 than upon number one's observation. 



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