74 MOLLUSCA OF SOMERSET. 
LITTORINA NERITOIDES, Linné. 
Gwyn Jeffreys observes concerning this common species, 
that it is probably the only kind of Littorina common to the 
north and extreme south of Europe. Mr. Corder records it 
from the Burtle Beds at Perry Green, Wembdon. 
Between Burnham and Brean, Minehead, ete. ! 
LiTTORINA RUDIS, Maton. 
Common, very plentiful on stony beaches. Mr. Bolton found 
it in the holocene deposit at Dumball Island, Avonmouth. 
Weston-super-Mare; F. A. Knight. 
Minehead ! 
LITTORINA LITTOREA, Linné. 
One of the commonest representatives of the genus. Jetireys 
observes that the old English name of “ periwinkle ” is sup- 
posed to have been a corruption of petty winkle or wilk. Mr. 
H. Corder records it from the Burtle Beds at Perry Green, 
W embdon. 
Weston-super-Mare; F. A. Knight. 
RISSOIDZA. 
Rissoa PARVA, Da Costa. 
Minehead ! 
ONOBA STRIATA, J. Adams (= Rissoa striata, J. Adams). 
Common under stones and amongst seaweeds. 
Weston-super-Mare ; F. A. Knight. 
ASSIMINEID#£. 
PALUDESTRINA STAGNALIS, Baster (=Hydrobia ulve, Pen- 
nant ). 
This species occurs in extraordinary numbers on the mud 
flats at the mouths of all our tidal rivers. Mr. Corder records 
it from the Burtle Beds at Wembdon; and Mr. Bolton, from a 
shell-bearing gravel at Dumball Island, Avonmouth. 
Weston-super-Mare; F. A. Knight. 
“ River mouths on the Somerset coast” ; Norman. 
PALUDESTRINA VENTROSA, Montagu (=Hydrobia ventrosa, 
Montagu). 
Abundant in brackish waters. 
