13. MYSCA solida. Shell thick, ponderous, and 

 somewhat cylindrical, conically tapering to a point 

 at the anterior end ; beaks wrinkled. 



Mysca solida. Turton, Dith. p. 246. t. 16. f. 2. 

 Mya ovata. Donovan, iv. t. 122. 



Shell two inches long and three and a half broad, 

 nearly cylindrical, covered with a blackish-brown 

 skin, thick and solid, with the front margin thick 

 and very obtuse ; beaks rugged and often decor- 

 ticated. 



In the Avon, near Bristol. 



