226 CO^CHYLW—niTHYRA. 60. 



removed without destructive violence. And this attachment is 

 effected, either by a solid elliptic testaceous appendage, which 

 pierces and fits the perforation in the lesser or under valve, and 

 is dilated and firmly adhesive at its base, as is represented in our 

 plate 17, fig. 10 ; or is a mere tough tendinous plug, as is the case 

 with most of those which are attaciied to Tuci. 



The great irregularity of figure and substance in many of the 

 species, occasions such difficulty of discrimination, that' we do not 

 think the genus has as yet been well understood, or clearly elu- 

 cidated. 



Montagu confines tiie British species to Anomia Ephippium, 

 A, undulata, A. aculeata, and A. cylindrica : but our own re- 

 searches, chieHy among the rocky shores of Devonshire, have led 

 us to the belief, that much curious matter yet remains for further 

 developement, and a more accurate investigation of this hitherto 

 obscure genus : and we submit our own conclusions, respecting 

 the determination of species, to the correction of better expe- 

 rience. 



In our figures, all drawn from specimens taken alive, it has 

 been our wish to present them in their less known stages of growth, 

 or to exhibit their remote and more dissimilar appearances and 

 alliances. And it may be proper to remark, that in our specific 

 description, we consider the lesser valve, or that which is perfo- 

 rated, as the under one, 



eleetiica. Anomia testd subot'biculari, subundalu, pellucidd, succined. 



Shell somewhat orbicular, with the surface a little undulate, 

 transparent, and amber-color. 



