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The variety of fpecies of Shells is immenfe, and their curious marks and variegated 

 colours are no lefs objects of our aftoniihment and delight. Accordingly, many great 

 Princes, as well as other illuftrious and learned perfons, in all ages, have fpared no 

 expenfe to form fuperb collections of thefe elegant fubjects. It has however been 

 remarked that few writers, except profeffed conchologifts, have beftowed on the ftudy 

 of Shells that degree of praife to which it feems entitled ; nor has any work on the 

 fubject hitherto appeared, either fufficiently copious, or ponefling any other kind of merit» 

 fuch as might render it worthy of general approbation. 



This in part may be afcribed to the employment of draughtfmen, painters, engravers, 

 and colourifts, ill qualified for this bufmefs; or who, however adequate to fuch an 

 attempt, have neverthelefs neglected to give that minute attention to the execution 

 of their refpective departments which the exigence of the fubject required. 



Complicated fyflems, bad arrangements, and the practice of crowding many (hells 

 of different families into one plate, have not only confufed the fubject, and created a 

 diftafle to the fcience itfelf, but made it neceffary that even the moil experienced 

 collector mould have fome clew to conduct him through thofe labyrinths of difficulties. 



The firft and chief duty incumbent un the conchologift who wifhes to eftablifh a 

 fyftem worthy of adoption, is a fcrupulous and minute attention to the figure, mouth, 

 extremities, and convolutions of thofe fhells which he claffes in the refpective families; 

 a neglect of this, joined to the method too generally followed, of exhibiting in prints, or 

 drawings, only one view of each fhell (a method which in a multitude of fpecies can 

 convey but a very imperfect knowledge of the fubject), hath not a little contributed to 

 the confufion fo juftly and univerfally objedted. 



These errors, which have hitherto proved fatal to many adventurers in this branch 

 of fcience, will here, to the befh of the author's judgment, be fludioufly avoided; and as 

 a fyftem will be given which he flatters himfelf will be found to ftand on the firm and 

 unalterable bafis of truth and nature, fo all pofiible diligence will be employed in the 

 execution of the work, to explain and illuftrate that fyflem by figures, in fuch a manner 

 as to imprefs intuitively a full and clear idea of the principles on which his new 

 claffification will depend. Accordingly the fynoptic table will not appear, till fufficient 

 progrefs fhall have been made in the work, to prepare the mind of the ftudent for a 

 candid decifion on its comparative merits; and this, the author takes the liberty of 

 pbferving, feemed to him the leaft exceptionable mode of fubmitting to the public this 



attempt 



