15 



** Oblique and inequilateral. 



5. Cyclas amnica. Shell obliquely oval, tumid, with 

 regular transverse grooves, and the beaks tumid 

 but not tubercular. 



Cyclas amnica. Turton, D'ltJi. jj. 250. ^. 11./. 15. 

 Tellina amnica. Wood, p. 153. t. 47./. 6. 

 Cardium amnicum. Montagu, ^.86. 



Shell three-eighths of an inch broad, brownish or 

 blueish horn colour, sometimes yellow towards the 

 margin, produced and narrower on one side, often 

 covered with a ferruginous coat. 



In slow rivers and streams. 



6. Cyclas apjoendiculata. Shell obliquely oval, very 

 tumid, with regular transverse grooves ; the beaks 

 very tumid and somewhat tubercled. 



Cyclas appendiculata. Leach, MSS. 

 Tellina Henslowensis. Sheppard. 



Shell about half the size of the last, from whicli it 

 differs, in its greater convexity, and the protrusion 

 of the beaks, at the base of which is a groove or 

 dark zone giving them the appearance of tuber- 

 cular appendages. 



In slow streams, but very rare. 



