THE MARINE FAUNA OF THE BLACKWATER ESTUARY 19
Order Actiniaria
ACTINIIDAE
Actinia mesenbryanthemum Linne
Recorded by the Essex Field Club in the Blackwater in 1888
(Cole, 1888).
Tealia felina (Linne)
Common on the lower shore and in bottom samples in sand
Bradwell shore (29.5.1963), Knoll Buoy (10.5.1963), etc.
Sagartiidae
Sagartia elegans (Dalyell)
One record only from the bottom fauna; Cocum Hills
(16.3.1963), but also taken from the water intake culverts at Brad-
well Power Station (25.6.1965).
Cereus pedunculatus (Pennant)
Only recorded from Bradwell Power Station water intake
culvert (25.6.1965).
Phylum CTENOPHORA
Class TENTACULATA
Pleurobrachia pileus (O. F. Muller)
Abundant in the plankton during April and May of most
years, but less common in the summer. Numbers tend to build up
over the winter.
Class NUDA
Beroe cucumis Fabricius
Occasional specimens taken throughout the year but most
frequently in June (1960 and 1961).
Phylum PLATYHELMINTHES
Class TURBELLARIA
Order Tricladida
Procerodidae
Procerodes ulvae (Oersted)
Common in pools on the upper shore and in saltings where
freshwater is flowing. Bradwell shore (29.5.1963).
Phylum NEMATHELMINTHES
Class NEMATODA
Nematodes are very common in the bottom and littoral sedi-
ments but no identifications have been attempted.
Phylum ROTIFERA
Rotifers are frequently seen when examining algae and detritus
from bottom samples and have also been recorded in the plankton
(April-June 1963). No identifications have been attempted.