MOLLUSCS 

 B. PELECYPODA 



Drtisiensla polymorpba (Pall.) Canals as far Sph&rium ovale (Fr.) Canals : Stoke-on- 

 north as Stoke-on-Trent. Specimens Trent ; Froghall ; Stone ; Dudley Port 



have been found containing pearls lacustre (Mtill.) 



(North Staff. Field Club Report, xxxiv. Pisidium amnicum (Mull.) 



65) pusil/um (Gmel.) 



Unto pictorum (Linn.) fontinale (Drap.) Common (the form 



tumidus, Retz. P. henslowianum occurs at Lichfield) 

 Anodonta cygntea (Linn.) milium (Held.) Froghall ; Milford ; 

 Sphterium rivicola (Leach) Coppenhall 



cerneum (Linn.) 



79 



