Fig. 7. Snails and finger-nail shells of special value as the food of fish. 

 Xos. 1-9, small Orb-snails (Planorbis defiectus, Planorbis parvus, and Planorbis 

 exactions) ; 1015, Valvata Snails (Yalvata tricarinata and Valvata bicarinata 

 normalis) ; 16-18, fresh-water Limpet Snails (Ancylus fuscus, Ancylus paral- 

 lelus, and Ancylus tardus) ; 19-21, Amnicola Snails (Amnicola limosa and 

 Amnicola lustrica) ; 22-23, Bythinia Snails (Bythinia tentaculata) ; 24, Amber 

 Snail (Succinca avara) ; 25-28, Pisidium Clams (Pisidium variabilc, Pisidium 

 compressum Icevigatum, Pisidium compressum, and Pisidium cequllaterale) ; 

 29-30, Musculium Clams (Musculium securis and Musculium rosaceum) ; 31-33, 

 Sphffirium Clams ( Splicer ium striatinum and Sphcerium vermontanum) ; 3436. 

 Tadpole Snails (Physa ancillaria warreniana and Physa Integra) ; 37-38, Pond 

 Snails (Lymncea columella chalybca and Lymncua columclla) ; 39-40, Snails 



(Gillia altilis and Somatogyrus subglobosus) ; 41, Tadpole Snail (Physa 

 gyrina) ; 42, Slender Pond Snail (LymncKa haldemani) ; 43. Pond Snail (Lym- 

 n(Ka palustris) ; 44, the larva of a Caddis-fly which resembles a snail in form 



(Helicopsyclie borealis) . 



