PSAMMOBIA. 



■ » • 

 Lam, 



TESTA transversa, oblonga, ad utramque extre- 

 mitatem paululiim hians: dentibus duobus 

 cardinalibus in valva altera, unico in altera. 

 Ligamentum externum. Impressiones muscu- 

 lares in utraqiie valva duae, suborbieulares, 

 distantes; impressio pallii sinu maximo. Epi- 

 dermis tenuis, cornea. 



A Genus established by Lamarck, consisting of a combi- 

 nation of several species taken from the Linnean Tellinae 

 and Solenes ; but to which we think it necessary to add 

 one or two cognate species from the Linnean Veneres and 

 the whole of theLamarckian Genus Psa7nmotcea, respecting 

 which he makes use of the remarkable expression that the 

 species of which it consists are only degenerated Psammo" 

 bice'' Indeed we do not hesitate to assert that the smaller 

 number of hinge teeth, which forms the principal dis- 

 tinguishing character of F&ammotcea according to him, is 

 a quite accidental circumstance, arising from some of the 

 teeth having been broken away : for when the hinge teeth 

 are perfect, there are as many as in Psammohia, It may 

 now seem desirable to ascertain how far it might be 

 proper to unite De Blainville's Genus Sokcurtus (which 

 ought to be Solenicurtus) with Psammohia, Upon this 

 subject we may observe that we think this Genus established 

 upon as good a foundation as any of the usually received 

 genera : the principal differences are as follows, in Soleni- 

 curtus both ends of the shell are usually rounded, whereas 

 in Psammobia one end is generally more or less angular; 



