230 



POPULAR CONCHOLOGY. 



tially external; the shell compressed, rather equivalve, 

 dull, and nearly smooth. Animal compressed, oblong, or 

 suborbicular ; mantle open, its margins distinctly denti- 

 culated ; siphonal tubes long, separated throughout, their 

 orifices plain ; foot large, linguiform, compressed ; labial 

 palpi large and triangular. — Few species ; also fossil. 



Some species from the Mediterranean, and one on our 

 own coasts, the Mactra piperata of Gmelin. 



Erycina. Lam. (Syndosmya Recluz ; Abra Leach.) — 

 Shell transverse, sub-inequila- 

 teral, equivalve, rarely gaping ; 

 two unequal cardinal teeth di- 

 verging, having a pit between 

 them; two oblong, compressed, 

 short lateral teeth ; ligament in- 

 ternal, placed in a triangular 

 hollow ; pallial impression deeply 

 sinuated. Animal scarcely to be 

 distinguished from Tellina; the 

 mantle is widely cloven and lengthened into two separate 

 siphons, of which the upper one is the shorter ; the foot 

 is long and compressed. — Several species ; also fossil. 



The species are found on the European coasts ; Forbes 

 illustrates four species as British under the generic name 

 of Syndosmya, and one comes from New Holland. E. 

 Boysii, tenuis, prismatica, &c, were arranged by Lamarck 

 in the genus Amphidesma. 



Embla. Loven. — Shell equivalve, gaping behind, trun- 

 cated ; ligament lying internally in a hollow of each valve, 

 behind which, in the right valve, is a hinge tooth, whilst 

 the left valve also presents a corresponding hollow ; the 

 latter has two lateral teeth ; the right a hollow, but no 

 lateral teeth ; a broad, doubled, pallial impression, with 



Erycina. 



