St 



We trufl the ingenious author of the work firft referred 

 to, will, as well as others, excufe us when we have occafion 

 to differ in opinion with them. It is a duty the public has a 

 right to expect from every writer, more efpecially in the cul- 

 tivation of fcieitce that profefles to difcourfe upon jjarticular 

 fubjedls, he fliould offer his own opinion. As this auth )r ob- 

 ferves, we have taken many fliells fimilar to Cardiumfpinofum 

 on the coafl of Devon; but we muft acknowledge we cannot 

 perceive the fmalleft difference between thofe and the Cardium 

 aculeatum. It muft be admitted that there is confiderable dif- 

 ficulty in identifying feveral Ipecies of this genus before they 

 arrive at full maturity, itis therefore elTential to their dilcrimi- 

 nation that fuch fhells fliould be examined in all their various 

 ftages of growth, and it is by this means we are enabled to 

 ofierour opinion. In the more infant ftate of the aculeatum 

 it is fo extremely like Cardium ciliare, that, if they are not the 

 fame, we are unable to point out the fmallefl; dillinftion, 

 and confefs that popular opinion induced us to originally 

 defcribe them as diftin6l in Tejiacea Britatinica ; whereas 

 having recently procured a great many of thofe fliells, with 

 all the intermediate ftages from the fize of a pea, to that of 

 near four inches in diameter, the largeft of which is we 

 believe confidered as the aculeatum of LinnjEus, there ap- 

 pears every reafon to believe the ciliare is a6lually the 

 young of that ipecies, and the fpinojum an intermediate 

 growth of the fame ; at leall: there does not appear to us any 

 difrerence between the fliell referred to in the Britifi Mif~ 

 cellany, which came from Torbay, and thofe in our cabinet ; 

 nor does the defcription convey any diitinction. It fhould 



be 



