NOTES : ORIGINAL AND SELECTED. 267
in a 30-acre field at Tolleshunt D'Arcy, over two miles as the crow flies
inland from the nearest part of the Blackwater river. The nest hollow
was lined with bits of broken shells and stones, in a rather open bit of
ground among the peas.—F. C. R. Jourdain.
Rare Birds in Essex.—Mr. W. E. Glegg, in British Birds, for May,
1929, records the following birds seen by him on the Lea Valley Reservoirs
during the severe weather of February and March last.
On February 16th a female Velvet-Scoter (Oidemia fusca) and on
March 3rd two female ditto were noted. On March 3rd a male
and female Common Scoter (Oidemia nigra) was observed. Mr. Glegg
remarks that the Common Scoter has only once before been recorded
from an inland locality in the county, and no Velvet-Scoter has been so
recorded to his knowledge.
A Scaup (Nyroca marila) was seen on February 15th and 16th and
two 011 March 3rd.
On March 2nd, Mr. Glegg noted an unusual concourse of Common
Pochard (Nyroca ferina), there being at least three hundred of these birds
on the Racecourse Reservoir at Walthamstow.—Editor.
Masses of Alga on the Eagle Pond, Snaresbrook.—During the
latter part of March last, large parts of this pond, especially at the western
end, were covered with dense masses of a very dirty-looking filamentous
alga which proved to be Rhizoclonium hieroglyphicum. The filaments were
much interlocked and mostly covered with a brown incrustation and
with the little blue-green alga Chamaesiphon incrustans. Mixed with
the filaments of Rhizoclonium were a few threads of Spirogyra, Mougeotia
and Oscillatoria and also pieces of Nitella and Elodea, all in a very dirty
and disordered condition. No doubt all this material had come up from
the bottom, where it had been in a resting condition during the winter ;
apparently it gradually sank again, for the amount on the surface steadily
diminished and the pond was quite clear early in April.—D. J. Scourfield.
Purple Sulphur-Bacteria in Masses on Floating Leaves.—On
the occasion of the Club's visit to the Highams Park district on the 16th
March last, a peculiar phenomenon was seen on a pond in the grounds
of "The Chestnuts," Oak Hill. Numerous semi-decayed leaves were
floating on the surface, all of which were covered with a bright red-purple
material, giving a very striking appearance to the pond. The purple
material came off the leaves in little flocks, and was found to consist
mainly of the sulphur-bacterium Lamprocystis roseo-persicina with a few
pieces of Thiopedia rosea. The water of the pond was not at all red, but
distinctly green, caused by the presence of a species of Chlamydomonas
A few specimens were also seen of that singular compound organism
Chlorochromatium, which consists of a central hyaline flagellated rod
(a bacterium ?) surrounded by a cylinder of excessively minute green
grains (blue-green algae ?), thus foreshadowing it would seem the sort of
symbiosis occurring in the lichens.—D. J. Scourfield.