A BAMBLE OVER THE LONDON CLAY. 49 



shells found in the vicinity of Fulham, includes 

 Planorbis corneus, carinatus, and vortex. In ad- 

 dition to these localities, may be named the Brent 

 and the Lea, the reservoirs at Kingshury and 

 Elstree, and ponds at Edgeware and Stanmore 

 Marsh, where most if not all of the above-named 

 species may be looked for with success. The mud- 

 shells (Limncea) are quite as numerous and generally 

 distributed. Cooper, in the list referred to, gives 

 ten species as occurring in the neighbourhood of 

 London ; but these are reducible to six, since two 

 of them, scaturigmum and fragilis, are respectively 

 the young and a variety of stagnalis, and a third, 

 glutinosa, a local species, belongs to the subgenus 

 Amphipeplea.* The commonest are peregra (with 

 a variety ovata) ; stagnalis (PL VI., fig. 8), of which 

 there are many varieties ; and auricularia, the ear- 

 shaped mud-shell (PL VI., fig. 9). The last named 

 has been met with in the ponds on Hampstead Heath. 

 Limncea glabra has been met with in a pond near Nine 

 Elms, and formerly near Vauxhall, and L. palustris 

 (PL VI., fig. 7) is not uncommon in the marshes 



* L. glutinosa has been found at Stanmore, Middlesex, 

 on the leaves of the yellow water-lily, Nuphar lutea. 



E 



