230 PKOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Yar. sulcylindrica, Jeff. Thames at Hampton Wick ; also at 

 Hammersmith (T. D. A. Cockerell, S.G., 1884, p. 236). A sinistral 

 example is recorded from Sunbury (J.C, iv, p. 37). 



90. Yalvata cristata (Miill.). 



Harefield, Uxbridge, "West Drayton, near Colnbrook, Greenford 

 Green, Acton, Bedfont, Fulham, Hackney Canal, and Ponders End. 

 Other records are Hampstead and Hendon (C. C. Fryer, 8.G., 1889, 

 p. 259). 



91. PoMATIAS ELEGANS (Miill.). 



Old chalk-pit at Harefield. 



92. Neritina fluviatilis (L.). 



Colne at Uxbridge Marsh (attached to stems of Ranunculus fluitans), 

 also near Staines. Canal at West Drayton, Lower Halliford, Chertsey, 

 Thames at Hampton Wick, Grand Junction Canal in several places, 

 Eiver Lea at Tottenham. It is fairly abundant in the Thames. Other 

 localities are Hendon (C. C. Fryer, S.G., 1889, p. 259); Enfield 

 (S. C. Cockerell, S.G., 1883, p."9); New River at Palmers Green 

 (G. H. Weaver). 



93. Dreissensia polymoepha (Pallas). 



Thames at Twickenham (alive), Grand Junction Canal, Alperton 

 (mostly dead shells). 



It is said to be abundant in the New River, and has been found in 

 the moat in front of the Royal Mint {Countryside, vol. v, p. 6). 



94. TJnio pictortjm (L.). 



Canal at Yiewsley and West Drayton, Colne at Staines, Tliames at 

 Hampton Wick and Twickenham, canal at Willesden, and Lea at 

 Tottenham. 



It has also been taken at Hendon (C. C. Fryer, S.G., 1889, p. 259) ; 

 River Brent (T. D. A. Cockerell, S.G., 1884, p. 138); Twyford (S. C. 

 Cockerell, S,G., 1887, p. 43) ; Enfield (S. C. Cockerell, S.G., 1883, p. 9). 



95. Unio tijmidus, Retz. 



Harefield, Colne at Uxbridge, canal at West Drayton and Yiewsley, 

 Southall ; Thames at Staines, Hampton Wick, and Twickenham ; 

 Paddington Canal, Hampstead ponds, and Lea at Tottenham. 



It is also recorded for Hendon (C. C. Fryer, S.G., 1889, p. 259); 

 Enfield (S. C. Cockerell, S.G., 1883, p. 9). 



An extremely prettily tinted variety was found when the water was 

 drawn off in Regents Park after the terrible skating accident in 1867, 

 and received at the time the name of Unio Richensis, after the dealer 

 who brought it to notice (Harting, "Rambles in search of Shells,'' p. 37). 



96. Anodonta cygnea (L.). 



Abundant in rivers, canals, and ponds. The small form (var. anatina) 

 is much commoner than typical A. cygnea. 



