90 



If we had followed the dic^tate of iinreferved credulity, at 

 leaf! twenty additional fpecies might have been given in this 

 work ; but fuch have been carefully excluded from our 

 cabinet of £n7//Z> Tejiacea where doubts exifted, or when, 

 upon a ftrlc^l: invelligation, there were reafons for conjc^bu- 

 ring a mixture of foreign and domellic had occafioned mif- 

 take, and no fucceeding communications from the fame 

 quarter had brought to light any thing to invalidate our for- 

 mer opinion. 



It is really furprifing to obferve how frequently fubje6ls 

 in natural hiflory are brought together as varieties of the 

 fame fpecies that have invariable chara61:eriftic marks of 

 diftindlion ; and others deftitute of any eflential difference 

 are divided into diftindl fpecies. That age occafions con- 

 fiderable variety will readily be admitted, and where oppor- 

 tunity has been wanting to trace the gradations from the 

 infant to the adult ftate, feveral Ipecies are fometimes made 

 out of one. Into this error we are all liable to fall, but can- 

 dour demands the truth when difcovered.and certainly there 

 is as much merit in difcovering the truth, as there is in dif- 

 covering a new fpecies* 



When in the former part of this work we gave the 

 Cypraa arctica and bullata diftinft places, it was for vv ant of 

 lufficient evidence to enable us to aftually differ in opinion 

 from refpediable conchologiffs ; although it will be feen 

 that we did exprefs fome doubt on the fubject. Since that 

 period fufiicient opportuuity has offered to colleft thefe fliells 



in 



