784 FAUNA AND FLORA OF NORFOLK : NON-MARINE MOLLUSCA. 
With a view to bringing the record of this branch of our 
local natural history up to date, I have compiled the present 
list, which contains notice of several species not hitherto 
recorded for the county, and many additional localities for 
the more uncommon kinds whose presence has already been 
recognised. For the sake of completeness I have included 
past records from every available source. 
Comparing Norfolk with the neighbouring county of Suffolk, 
it is noticeable that the Rivers Yare and Bure yield a much 
greater abundance of molluscs than do the Gipping, Deben and 
Aide, especially of the larger bivalves. The broads also 
contain immense quantities of the commoner kinds. But the 
upper reaches of the rivers, and the ponds of .the upland 
districts, although not so abundantly teeming with life, 
produce a greater variety of species. 
Of Land Snails the uplands are inhabited by the larger 
kinds : — Helix, Helicella, etc., while the smaller species seem 
to prefer a moister situation in the river-valleys. 
The fens in the valley of the Little Ouse and Waveney, are 
particularly rich in molluscan life. At Roydon Fen, near 
Diss, I have taken from a couple of handfuls of flood rejecta- 
menta, more than thirty species of land and freshwater shells, 
including two of the rarest British species, viz., Vertigo 
moulinsiana and V. angustior. It is also remarkable that all 
the English species belonging to the genus Vertigo except 
alpestris, a northern form, occur in this valley. 
The arrangement and nomenclature are in accordance 
with the ‘ List of British Non-Marine Mollusca.’ prepared by 
Mr. B. B. Woodward, F.L.S., and published by the Concho- 
logical Society of Great Britain and Ireland. 
The brackets placed around the name of an authority 
signify that the species has been removed from the Genus 
in which the author originally placed it. 
Of the 144 living species considered as indigenous to the 
British Isles, hi are here recorded as found in Norfolk. 
Most of the others are apparently confined to counties remote 
from East Anglia, so that the list may be considered almost, 
if not quite, complete. 
