CONCHYLIA— JD/TifyRJ. 4. 21 



hinge near one end where it is rounded : the other end truncate and 

 open nearly half way across, with often three or four longitudinal 

 laminar ridges on the inside : this side is also more or less angular, 

 in consequence of a raised ridge extending from the beak to the end, 

 and which is often a little rough like the Hiatella minuta. 



The valves are sometimes pressed close together at the truncated 

 end, causing the opposite or rounded side to open widely, in which 

 state it has much the appearance of the Gastrochaena pholadia, and 

 we have observed it marked as such in cabinets ; but attention to 

 the following particulars will always distinguish it. The elongated 

 side is truncate; it wants the small laminar teeth in the valves; 

 and on the back part at the rounded end the valves do not meet 

 together. 



Saxicava testa ovatd, transversim striata, extremitatibus rotundatis Pholadis. 



subhiantibus '■ 



Shell oval, transversely striate, rounded and somewhat open at both 

 the ends. 



Tab.nost. 2, fig. 11. 

 Mytilus Pholadis. lAnn. Mant. p. 548. 



Linn. Iter. Westgoth. tab. 5, fig. 2. 

 Gmelin. Syst. p. 3352. 

 Turton, Linn. Syst, iv. p. 95. 

 Muller, Zool. Dan. iii. p. 12, tab. 87, fig. 1 to 3. 

 My a byssifera. Fabricius, Faun. Groenl. p. 408. 

 Mus. nost. Rocks in Torbay. 



