140 THE ESSEX NATURALIST
Cribraria aurantiaca Schrad.
Enteridium olivaceum Ehrenb.
Trichia scabra Rost.
T. varia Pers.
T. floriformis (Schw.) G. Lister.
Arcyria ferruginea Sauter.
A. cinerea (Bull.) Pers.
A. pomiformis (Lees) Rost.
A. incarnata Pers.
A. denudata (L.) Wetts.
Perichaena depressa Libert
Ordinary Meeting (1013th Meeting)
SATURDAY, 26 OCTOBER, 1957
This meeting at the West Ham College of Technology was attended by
thirty-six members and friends and the chair was taken by the President,
Mr. E. E. Syms.
Mr. Bernard Ward showed, on behalf of Mr. E. P. Williams, a curious
"double" oyster shell discovered at West Mersea on October 19th last.
One, a very large specimen of apparently great age, had a small oyster
attached to one surface. The small shell had a deposit of nacre on its outer
surface which appeared to indicate that, during the early part of its life,
it had existed within the shell of the other. There was some discussion when
the specimen was examined by several biologists present and not all were
convinced that this was the correct explanation of the phenomenon.
Dr. I. F. Hayward exhibited recently collected material from Clacton
and Jaywick. It included an upper molar of Elephas antiquus in very good
condition and some scrapers and other worked flints of Neolithic age.
He also showed various artifacts of Clactonian age which included two
possible hammer-stones. He had discussed these with Mr. Hazzledine Warren
who had agreed that in examining his own collection he had recognized
specimens which could probably be regarded as hammer-stones. This might
call for a modification of the contrary belief that only anvil-stones were used
by Clactonian Man.
The President exhibited photographic lantern slides of the eggs, larvae,
pupae and imagines of the beetle Endomychus coccineus L., a local beetle
which occurs in Epping Forest. (see p. 121).
Dr. Rudge gave an account of this recent inspection of the eastern
boundary stones of the ancient Forest of Waltham, (see p. 117). He illus-
trated his account with colour transparencies showing the present state of the
stones.
Mr. Bartrop showed a fruiting plant of the Thorn-apple (Datura stramonium
L.) from his garden at Oak Tree Cottage, Margaretting. In 1946/7 the garden
was first made from pasture land and the following year a thorn-apple plant
appeared on a vegetable plot. It was allowed to seed and the following year
two plants appeared on the same spot. These were also allowed to seed but there
were no further plants until about 1953 or 1954, when there was one plant