193
REPORT ON MARINE SPECIMENS DREDGED
FROM THE ESTUARIES OF THE ORWELL
AND STOUR ON THE OCCASION OF THE
CLUB'S DREDGING EXPEDITION, 23 JULY, 1910,
By HENRY WHITEHEAD, B.Sc.
[Read 29th October 1910.]
THE specimens obtained from the Orwell and Stour in July
last were handed to me as Assistant-in-charge of the
Museum during the absence of the Curator. They had been
preserved temporarily in a 6% solution of formalin in sea-water.
This solution was changed for one of 4% in tap-water, but the
Crustaceans and Sponges were transferred to 75% spirit. The
bulk of the material has been mounted permanently in rect-
angular specimen jars, and is now exhibited in the Museum.
The sea-weeds, preserved in formalin, were sent to Mr.
E. M. Holmes, F.L.S., who had kindly undertaken to name
them. His report is appended. The sea-weeds have since
been floated out and mounted as herbarium specimens ; duplicate
specimens being kept in formalin for microscopic examination if
necessary.
I take this opportunity of acknowledging the help thus
rendered by Mr. E. M. Holmes; by Prof. W. A. Herdman,
F.R.S., who named the specimens of Tunicata ; and by Dr.
W. T. Caiman and Mr. R. Kirkpatrick, both of the British
Museum, who examined and named most of the Crustacea and
Sponges.
The Sea-weeds, Sponges, and Hydrozoa were carefully
examined and washed, and the washings sieved. By this means, a
number of small Crustaceans and Pycnogonida were obtained.
Dr. Caiman's examination of this material has yielded some
interesting results, notably a number of specimens of a small
Pycnogon, Ammothea echinata, found on Hydrozoa and sea-weeds.
Dr. Caiman says "So far as I know, there is only one East
Coast record for . . . [this] species (A. echinata) and that a very
old one from Seaham." Dr. Sorby spent a good deal of time
dredging in the Orwell, but his list of Pycnogonida1 does not
contain this species, and it is scarcely likely that its occurrence
would have been overlooked by such a keen observer. The
circumstance may probably be explained when we realise how
1 Victoria History of Essex, vol i. (1903), p. 81.