XXVUi MOLLUSCA OF SOMERSET. 
Vitrea alliaria, Miller. 
Zonitoides nitidus, Mviller (local). 
Arion subfuscus, Draparnaud. 
Arion hortensis, Férussac. 
Arion fasciatus, Nilsson. 
Pyramidula rotundata, Miller (common). 
Hygromia hispida, Linné (common). 
Hygromia rufescens, Pennant (dominant). 
Cochlicopa lubrica, Miller. 
Carychium minimum, Miiller. 
H. hispida occurs in great numbers wherever nettles fringe 
the rhine, it bears submergence well, and may be not in- 
frequently found crawling on the stems of aquatic plants. 
Ayriolimax agrestis 1s apparently the only species in this 
association which is unable to survive prolonged  sub- 
mersion. I noticed, in several localities which had _ been 
recently flooded, this species lying dead, obviously drowned, 
in some numbers near the margins of the rhines. 
The edges of the rhines are fringed with aquatic plants, 
characterised by their upright leaves, e.g., Phragmites com- 
munis, Trin. ; Iris pseudacorus, Linné ; Typha latifolia, Linné : 
and Sparganium erectum, Linn. Crawling on their stems and 
leaves, often in large numbers, are : 
Succinea elegans, [isso (dominant). 
Succinea putris, Linné. 
Limneza peregra, Mviller. 
Limneza truncatula, Miller. 
The dredge-net obtains from amongst the submerged stems 
of these plants the following : 
Limneza palustris, Miller. 
Planorbis umbilicatus, Miiller (=P. complanatus, Jeffreys). 
Planorbis vortex, Linné. 
Planorbis fontanus, Liyhtfvot (=P. nitidus, Miller, of Jeffreys) 
Physa fontinalis, Linné. 
Valvata cristata, Miller. 
