MA1ACOZOA. TROPIOPODA. LAMELLIBRANCHIATA. 283 



in the left more prominent. Length four inches, breadth 

 about six-twelfths. 



Not very uncommon on the sandy coast. I have not seen 

 specimens of larger dimensions than those given above, al- 

 though in the Hebrides it nearly equals Solen Siliqua in size. 



Solen Ensis. Linn. Syst. Nat. i. 1 1 14 Solen Ensis. Turt. Brit. 

 Bir. 82. Solen Ensis. * Perm. Brit. Zool. iv. 84. PI. 45. f. 22. 

 Solen Ensis. Mont. Test. Brit. 48. Solen Ensis. Flem. Brit. 

 Anim. 459. Solen Ensis. Lamk. Syst. v. 452; Ed. 2. vi. 55. 



3. Solen pellucidus. Pellucid Solen. 



Shell much elongated, linear-oblong, slightly recurved, 

 rounded at both ends, with a delicate olivaceous epidermis ; 

 valves thin, pellucid, each with an elongated subtriangular 

 space, not readily distinguishable unless on being compared 

 with the other species ; the surface glossy, white, faintly varie- 

 gated with reddish ; the hinge close to the anterior extremity, 

 with two teeth in the left valve, one in the other, and in each 

 a posterior elongated marginal tooth. Length an inch and 

 three-fourths, breadth half an inch. 



Sometimes cast on the r r sandy beaches, and single valves 

 found adhering to Actiniae from deep water. 



Soleu pellucidus. Penn. Brit. Zool. iv. 84. PI. 46. f. 23; Ed. 2. 

 iv. 173. PI. 49. f. 2. Solen pellucidus. Mont. Test. Brit. 49. 

 Solen pellucidus. Flem. Brit. Anim. 459. Solen pellucidus. Turt. 

 Brit. Biv. 83. Solen pygmaeus. Larak. Syst. v. 452; Ed. 2. vi. 56. 



GENUS 2. PSAMMOBIA. 



Shell oblong or elliptical, equivalve, inequilateral, 

 concentrically striated, a little open at both ends. Um- 

 bones very small. Hinge with two small, erect, forked 

 teeth in the right valve, a single forked entering tooth in 

 the left, and frequently another smaller simple tooth 

 behind, the lateral teeth obsolete, merely forming a 

 thickened margin. Anterior end rather larger and 

 rounded, posterior longer, with a triangular space de- 

 fined by a ridge from the umbo to the lower posterior 

 angle, and slightly bent to the right. Muscular impres- 

 sions widely separated. Ligament external, and promi- 

 nent. 



Psammobia differs very little from Solen on the one 

 hand, and from Tellina on the other. From the latter 



