PSAMMOBIA. 391 



punicea of Gmelin (T. lata, Pulteney, and T. incequi- 

 striata, Donovan) may belong to the southern fauna of 

 Great Britain, as it inhabits the Mediterranean ; but I 

 do not think it ought to be admitted without farther 

 evidence. Pulteney is believed to have found it on the 

 coast of Dorsetshire ; Brown is reported to have dredged 

 a specimen off Holy Island, and gives " Leith shore " 

 on the authority of Sir Patrick Walker; and Mr. 

 Spencer brought me a couple of valves from Herm. T. 

 elliptica and T. pellucida of Brown are irrecognizable ; 

 the former is possibly the young of Tapes pullastra, and 

 the latter the fry of Lucina borealis. 



Genus III. PSAMMO'BIA * Lamarck. PI. VII. f. 4. 



Body oblong or elongated, compressed : tubes longitudinally 

 lineated or marked with rows of cilia ; orifice of each tube, or 

 only of the incurrent or alimentary one, furnished with den- 

 tate points. 



Shell oblong or elliptical, equivalve, nearly equilateral, 

 compressed, striated concentrically as well as longitudinally ; 

 posterior side somewhat truncate and gaping : teeth, two car- 

 dinals in each valve, the posterior one in the left valve being 

 disproportionately small and set obliquely, the others cloven ; 

 no laterals. 



Tellina and this genus are near neighbours ; but in 

 Psammobia the tabes are furnished externally with lon- 

 gitudinal rows of cilia, the shell is more or less equal- 

 sided and sculptured by longitudinal as well as con- 

 centric striae, and the posterior extremity has a decided 

 gape. 



Two other generic names [Lux, Chemnitz, and Gari, 

 Schumacher) have precedence of that given by Lamarck, 

 but they are antiquated. 



* Liying in sand. 



