188 THE LAND AND FRESH-WATER MOLLUSCA. 



Fam. Sphaeriidae. 



Sphaerium corneum (Lin.). Fossil M. ; Forth and Clyde Cnl. (D.) ; Paisley 

 Cnl. (C.). Locally though not gen. c. 



S. lacustre (Miill.). Fossil M. ; Forth and Clyde Cnl. at Firhill, possibly 

 introduced (B. D.). 



Pisidium amnicum (Mail.). Glasgow and Paisley Cnl. (C.) ; E. Clyde above 

 Etitherglen Bridge (B.). 



P. fontinale (Drap.). Possil M. ; ditch between Frankfield and Hogganfield 



(B.) ; E. Tarbert (T.). 

 var. henslowana (Shepp.). Glasgow and Paisley Cnl. (Mihi.). 



P. pusillum (Gmelin). Possil M. ; nr. Cloch L. H. (B.) ; Tarbert (C.); L. Fad 

 and L. Ascog (R). 



P. nitidum, Jenyns. Frankfield L. (B.) ; pools by side of road bet. Port- 

 Glasgow and Kilmalcolm (fide Ji G. Jeffreys) (G.) ; L. Fad (R). 



Sub-Order Heteromya. 



Fam. Mytilidae. 



Dreissena polymorpha (Pallas). Forth and Clyde Cnl. ; c., not native (B.) ; 

 Paisley Cnl. (C.). 



