CREPIDULA FORNICATA, L., OFF THE COAST OF ESSEX 37
been laid down, but never before this that American ones were also
employed for this purpose.
Having a meeting of the Essex Field Club next day at St.
Osyth, and along the sea-wall, I exhibited the shell, and subse-
quently made a note of it in The Essex Naturalist (Vol. v., p. 260,
Dec, 1891.)
I thought no more about this occurrence until the 4th of
March, 1893, when I received a small parcel of marine forms from
the Crouch river, taken by John Bacon whilst engaged in the
oyster fishery on board a Burnham smack. Amongst the contents,
fish, nudibranchs, etc., I found a living example of the same
Crepidula, which he mentioned in his letter as a "Crow oyster on a
Stone." It may be well to add that Burnham, close to which these
were taken, is about sixteen miles in a straight line from Stone
Point, and by sea round the coast of the Dengie Hundred and up
the river, over twenty miles. I wrote back at once to Bacon to ask
if this was the first shell of the kind he had seen, and requested
him to look out for more; to which he replied : "I can remember
these for fifteen to twenty years ; although I have known them so
long they are very scarce. I have caught them in different parts of
the Crouch and Roach rivers. I do not know, nor do I think, that
any American oysters or spat has ever been laid down in either of
our rivers."
Later on he told me that he had heard they were fairly common
in the Blackwater; but neither my friend Mr. Fitch, F.L.S., who
knows the river well, nor myself, has ever caught it whilst dredg-
ing, though we have taken over fifty species of mollusca in that
river.
On the 15th of April, Bacon sent me another live specimen, and
one to Mr. Fitch ; both of these were from oysters at the Ferry
layings (Cricksea). My specimen died during the night, but I took
it up the next day to the Natural History Museum to show Mr.
Edgar A. Smith ; and we there took out the animal and put it in
spirit. The shell of this is very concave, and rich in colour inside,
the septum pure enamel-white; and we then compared it with
shells from North America in the Museum, which were practically
identical.
When visiting Maldon, later on, Mr. Fitch gave me the other
shell. It is larger, flatter, and the inside colour more mottled ; and
the oyster on which it was found is not a native, but a French one