266
THE ESSEX NATURALIST
E, F and G. Within the Blackwater, the sample was collected
by a total of three grab hauls and two 50 m dredge tows; offshore
only the dredge was used (three 50 m tows per station). The
apparatus was operated from on board the MFV "Providence",
an inshore stern trawler, equipped with a Decca navigation
system. The latter allowed accurate fixing of the, collecting
stations, thereby facilitating future comparison of the 1970 data
with those obtained by further investigations.
The 1970 survey only investigated the Sublittoral regions of
the Blackwater, and not all the animal groups for which Davis
(loc. cit.) gave records were covered. Only macroscopic species
were included, and of these, some groups, e.g. the Polyzoa, were
largely neglected. The authors are responsible for the identifica-
tions cited here. These were made using the various publications
in the Faune de France series (for polychaetes, amphipods,
Pycnogonids, etc.), using specialist volumes such as Tebble (1966)
for lamellibranchs, Allen (1967) for decapod crustaceans, and
Millar (1970) for ascidians, and by the use of Eales (1967) and
the authors' personal knowledge for the remaining groups. A
description of the Sublittoral habitats in the Blackwater has been
given previously (Davis, loc. cit.). Samples were sorted on deck;
grab samples being first hosed over a 3 mm mesh sieve. Material
unidentifiable by naked eye was transported back to the labora-
tory for further study.
Additions and Corrections to the Fauna List
The following records are new to the fauna list:
Class ANTHOZOA
Order Actiniaria
Metridiidae
Metridium senile (Linnaeus)
Uncommon; recorded from stations C.3, S.18 and from the
Barrier Wall.
Class ENOPLA
Order Heteronemertini
Tetrastemmatidae
Tetrastemma flavidum Ehrenberg
Probably not uncommon, but easily overlooked. Recorded
from line 1, Stn 5.
Class POLYCHAETA
Aphroditidae
Lagisca extenuata (Grube)
Uncommon; recorded from station HB.2.
Phyllodocidae
Phyllodoce lamelligera Johnston