ARTIFICIAL PRESERVATION OF TIMBER. 



349 



Seven species of the teredo have been identified in North American 

 waters. They are the Teredo navalis, the Teredo norvegica, the Teredo 

 dilatata, the Teredo megotara, the Teredo thompsono, the Xylophaga dorsalis, 

 and the Xylotrya pmbriata. They are all similar in their principal char- 

 acteristics, but their range varies. Thus, the Teredo navalis inhabits 

 Atlantic waters, in America from Cape Cod to Florida, and in Europe 

 from Sweden to Sicily; and the Teredo norvegica from Cape Cod northward 

 to the coast of Maine; while the Xylotrya fimbriata abounds in North 

 Pacific waters. 





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mm 



WORK OF THE TEREDO. 



UNTREATED TIMBER COMPLETELY DESTROYED IN 

 18 MONTHS CAPE HAVTIEN, W. I. 



WORK OF THE LIMNORIA. 



SECTION' OF SPRUCE PILE, UNTREATED, AFTER 

 7 YEARS USE AT NEYVFONDLAND. 



The teredo is a true mollusk, and its popular designation of ship worm 

 is correct only in so far as its long thin body resembles a worm. In general 

 appearance it might be said to suggest a soft shell clam with an unusually 

 long neck and a very small shell. It is exceedingly destructive to nearly 

 all kinds of timber, and is most active in southern waters. The claim 

 has been made that the Australian jarrah is immune from its attacks, 

 but if this be true it is perhaps the only exception. 



One of the worst features of the work of the teredo is the minuteness 

 of the perforation which it makes in the outer surface when entering a 

 pile or piece of submerged timber. While these apertures may be almost 

 invisible, the destruction wrought within may be very great indeed, and 



