MAXACOZOA. 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. Turk Brit. 

 Biv. 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 sandy beaches, and single valves 

 found adhering to Actiniae from deep water. 



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

 iv. 173. PI. 49. f. 2. Solen peUucidus. 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 smaUer 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 



