17 



man, however, remarks the circumdance of fome of the 

 cafes being arched, or covered at the larger end. We muft 

 not afcribe this as the refultofthe animal having arrived at 

 full growth, as has been fuppofed, fince very fmall, as well 

 as large fpecimens are frequently obferved to poflefs it. In 

 pieces of timber which are over-flocked, they never can 

 grow to half their natural fize, becaufe their cells have no 

 room for extenfion ; and the confequence is, that after the 

 timber has been deflroyed in all directions, fome probably 

 die ; but the great work of nature having been performed, 

 the timber falls to pieces, and the animals become a prey to 

 fifli, the neceffary connedling link in the tranfmutation of 

 matter. 



It has been cuftomary to term that part of the Teredo 

 animal enclofed within the fliells, the head, and confe- 

 quently the paflkge from thence has been called the eelo- 

 phagus ; but whether it will flri6lly bear that appellation 

 muft be doubtful, fince the difcovery of an opening is the only 

 analogy it has to fuch a part, and that, moft adliredly does 

 not perform the office of a mouth, as has been moft clearly- 

 proved, and is admitted by Mr. Home, at leaft after the 

 animal has clofed up the larger end of its teftaceous tube. 

 If we reafon from analogy, the contrary would be the 

 opinion, for all teftaceous animals pofieffed of locomotion, 

 evidently have their fhell affixed to the pofterior end. 



The minute anatomical inveftigation of fo aqueous an 

 animal is attended with extreme difficulty, and we fear 



C admits 



