GALEOMMA. 109 



Guernsey, where they are only procurable at very low 

 tides in an extremely limited space, where a few can 

 occasionally be obtained by heaving over some of the 

 largest stones, beneath the hollowed bases of which the 

 valves are seen adhering to the rock, not in the ordinary 

 closed position of bivalves, but flatly expanded, and co- 

 vered with a thin white skin. Single valves in a worn 

 condition are found mixed with innumerable dead Rissoa 

 in the tiny bay of the islet, which is so noted for its 

 minute shells ; but even in that state they are not abundant. 

 Mr. Metcalfe and Mr. Barlee have found them in the same 

 locality. Mr. Clark procured it at Exmouth. The ori- 

 ginal locality given by Dr. Turton was the British Channel, 

 from whence he obtained them by the assistance of a 

 dredge. According to Mr. G. B. Sowerby, a single valve 

 marked "Ireland" was contained in the collection of 

 Humphreys. It appears to be frequent in the Western 

 Mediterranean. 



