48 
hedge banks and clumps of nettles, after a heavy dew or mild rain, 
seem almost alive with various Limaces and Helices. The young 
are hatched, and are getting on with their growtli, and others have 
arrived at maturity. It is supposed that Helices live about two 
years, and other genera may do the same. They are hatched in 
the summer, half grown by the winter, arrive at their full growth 
during the next summer, and die in their second hybernation. 
1 his I think probable, as the great majority of Helices one finds 
in the spring-are young ones with no lip formed. 
AQUATIC. 
SrHyERiuM CORNEUM (Liiiue.) Abundant. 
,, LACUSTRE (Muller.) Heigham. In the river. 
PisiDiUM AMNICUM (MuUer.) Common. 
„ FONTiNALE ( Hrapamaud. ) var. Hemslowana. Lynn. 
,, PusiLLUM (Gmelin.) Thorpe ditches. 
,, ROSEUM (Scholtz.) Heigham ditto. 
Unio pictorum (Linmi.) Abundant in almost every stream. 
„ VAR COMPRESSA. This variety is found at sharp angles of 
the river, and may be caused by the swiftness of the current 
carrying away the loose jjarticles of soil, and leaving a very hard 
bottom for the shell to live in. 
Anodonta cygnea (Linn6.) Common. 
„ ANATiNA (Linno.) Ditto. 
Dreissena polymorpha (Pallas.) Breydon. 
Neritina fluviatieis (Linno.) Heigham, on the leaves of 
water plants, posts, and roots of trees. 
Paludina contecta (Millet.) Common in streams romul 
M orwich. 
Paludina vivipara (Linn4.) Found with last-named species. 
Bytihnia tentaculata (Linne.) Common everywhere. 
„ Leachii (Sheppard.) On water plants with above. 
Valvata PISCINALIS (Mullcr.) Abundant. A tliiclc yellow 
^•ar. Lynn. Brackish water. 
Valvata cristata (Muller.) Common with Bithinia. 
Planorbis LiNEATUS (Wallvor.) Plentiful in ditches at 'I'horpe 
and Heigham. 
