120
THE ESSEX NATURALIST.
Trench 18. Fairly large fragment of the rim of a store-jar,
shown in Fig. 2, No. 4; diam. 161/2 ins.
Six small fragments, possibly seven, of the rim of a native
platter, Fig. 2, No. 11.
Three other small chips and a fragment of hard ware of
dubious date, but not later than La Tene III.
Trench 20. Six small chips of La Tene III ware and three
small pieces of daub, the rest is Hallstatt (q.v.).
Trench 21. A quantity of charcoal from a hearth.
Mr. Dunning has already described a triangular loom-weight
(Ant. Journ. XIV, p. 189, fig. 4) of the usual Iron Age type,
which measures just over 6 ins. on all three sides and 4 ins. in
thickness. It weighs 61bs. Further fragments were found in
the ditch with pieces of burnt clay, possibly crude brick or tile,
about 11/4in. thick, like that described ibid. fig. 3.
THE OCCURRENCE OF A MINUTE FUNGUS
ON A FREE-SWIMMING ALGA (a Chytrid on
Chlorogonium) IN AN EPPING FOREST POND.
By D. J. SCOURFIELD, I.S.O., F.L.S., Etc.
[Read 29th February, 1936.]
(With One Plate.)
IN the early part of November, 1934, the pond on Theydon
Bois Green was noticeably green in colour owing to the
presence of a great variety of microscopic unicellular algae. As
usual some of these were motile, moving through the water by
means of the lashing of their flagella, while others were non-
motile, simply remaining suspended in the water, as they can
do owing to their very small size and to the possession in some
cases of long spines and other outgrowths.
Among the motile forms were many specimens of a species of
Chlorogonium, a genus belonging to the Order Volvocales, and
very closely allied to the much more widely known genus
Chalmydomonas. It was a needle-like form, averaging about
one two-hundred-and-fiftieth of an inch in length, but some
twenty or more times longer than broad, tapering to a small
blunt end anteriorly and to a sharp point posteriorly. From its
general character it would seem to have been a very elongated
form of Chlorogonium elongatum.