216 MALACOZOA. TROPIOPODA. LAMELLIBRANCHIATA. 



rather thick, with numerous close concentric small ridges, 

 whitish with pink rays. Crdssus, thick. 



3. Tellina tenuis. Shell ovate, compressed, very thin, 

 glossy, concentrically striate, white, yellow, or pink. 

 Tennis, thin. 



4. Tellina Fdbula. Shell ovate, compressed, very 

 thin, glossy, white, with one valve concentrically, the 

 other obliquely striate. Fdbula, a small bean. 



FAMILY IX. SOLENINA. 



Animal much elongated, with the mantle closed, but 

 having an opening in front for the foot, and forming 

 behind a tube, internally double ; the foot conical. 

 Shell long, equivalve, extremely inequilateral, thin, gap- 

 ing at both ends, and covered with epidermis ; the hinge 

 with not more than two small, prominent teeth in each 

 valve ; the ligament linear and dorsal. Named from the 

 genus Solen. 



GENUS 1. SOLEN. Shell extremely elongated, linear or 

 oblong, equivalve, extremely inequilateral ; umbones 

 very small, near one end; cardinal teeth very small. 

 S6len, a razor-shell. Linnaeus. 



1 . S6len Siliqua. Shell extremely elongated, slender, 

 straight, truncate at both ends. Siliqua, a pod. 



2. Solen Ensis. Shell extremely elongated, slender, 

 rearcuate, truncato-rotundate at both ends. Ensis, a 

 sword. 



3. S6len pellucidus. Shell much elongated, linear- 

 oblong, slightly recurved, rounded at both ends. Pel- 

 lucidus, permeable to light. 



GENUS 2. PSAMMOBIA. Shell oblong or elliptical, in- 

 equilateral; umbones very small; cardinal teeth very 

 small. VdfjLjjios, sand ; /3tdo>, to live. Lamarck. 



1. Psammdbia Feroensis. Shell oblong, much com- 

 pressed, anteriorly rounded, posteriorly obliquely trun- 

 cate, finely striated .concentrically, with a prominent line 

 from the umbo to the posterior angle. Named from its 

 occurring in Feroe. 



