OBSERVATIONS. 



This is one of the several species of shells, which inha- 

 bit the northern shores of America, in common with the 

 coast of Europe, and particularly that of Great Britain, as 

 well as Iceland. The late Mr. Z. Collins, a zealous and 

 enlightened naturalist, presented to me an individual which 

 he found on the coast of Newjersey. The colour is whi- 

 tish, but when living, it is covered with a brownish deci- 

 duous epidermis. 



Although the name icehndicus has been adopted by La- 

 marck and other distinguished conchologists, yet with 

 Pennant, Dillwyn and others, I have retained the Linnae- 

 an name, for the allsulficient reason, that it has the priori- 

 ty ; whilst, at therame time, it has the advantage of being 

 preferable in itself, as the shell is not limited to Iceland. 



The resemblance between this shell and the antiquus, L. 

 has been noticed by many writers ; but that species is 

 much larger, more robust, the aperture more dilated, and 

 the striae much more crouded. Lamarck and others say 

 that they may be distinguished by the rectilinear beak of 

 the antiquus. This also is a good character but in my ca- 

 binet is a large and fine specimen of the latter, of which 

 the beak is as much recurved as in the present species. 



REFERENCE TO THE PLATE. 



The upper and lower figurc«. 

 FLATE XXIX. Q 



