PSAMMOBIA. 



in Solenicurtus the teeth are two in each valve, and they 

 are for the most part lengthened and curved, while in 

 Psammohia they are short and mostly bifid : the muscular 

 impression of the mantle also in Solenicurtus has a much 

 larger sinus than in Psammobia. 



Psammohia appears to be nearly related to Sangui- 

 nolaria, indeed we are of opinion, as we have before 

 stated, that several of Lamarck's Sanguinolariae should 

 be arranged with the Psammobiee, particularly his 

 S. rugosa, and S. occidens. 



Shell oblong, somewhat gaping at each extremity, 

 with two cardinal teeth in one valve, and one in the other. 

 Ligament external. Muscular impressions two, suborbi- 

 cular, distant, one placed near each end of the shell : 

 muscular impression of the mantle with a very large 

 sinus. Epidermis thin, horny. 



Many recent species of this pretty Genus are well 

 known, and some are common on our own shores, of these 

 the Ps. ferroensis is remarkable, inasmuch as it has an 

 approximation to the flexuous fold characteristic of 

 Tellina^ it is the Tellina ferroensis of Linnean authors. 

 Several fossil species are also known, which are mostly 

 confined to the tertiary beds ; and the green sand contains 

 at least one. 



* By an inadvertance in the descriptions of Tellina and Tellinides in 

 No. XXXI.^ we have reversed the anterior and posterior ends of the shell. We 

 must therefore request our readers to correct our expressions, and for posterior 

 to read anterior and vice versa. 



