5.5 



GLYCIMERIS, Lam. 



Gen. Char. Equal-valved, transverse^ thick, ga- 

 ping at both sides ; epidermis thick, extend- 

 ing beyond the edge of the shell; hinge-line 

 thick, toothless ; fulcra large, tumid ; ligament 

 external ; muscular impressions two ; impres- 

 sion of the attachment of the mantle deep, 

 broad, rugged, with hardly any sinus. 



A Genus related to Panopcea, and according to some, to 

 Solen, but distinguished from both by the absence of teeth 

 in the hinge, and the want of a sinus in the mantle : from 

 Soleyi it also differs in having more equal and rounded 

 sides. It is related to the Myaricc in having a thick pro- 

 jecting epidermis, which leaves the impressions of its 

 wrinkles upon the shell. The foot of the animal as well 

 as the length of its tubes must be however very different 

 from those parts in the MyaricE, as well as in the above- 

 mentioned genera. It is remarkable that the umbones are 

 often eroded. The recent species inhabit the Northern 

 Ocean. 



