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NOTES ON THE MOLLUSCA OF THE THAMES
ESTUARY, WITH A LIST OF SPECIES
OBSERVED.
By A. J. JENKINS, Member of the Conchological Society.
[Read November 7th, 1891.]
IN bringing before the Essex Field Club the following account of
the Mollusca inhabiting the Thames Estuary, I am free to
acknowledge that the list is by no means complete. When asked
by your Secretary some time ago to prepare an account of the various
species collected by myself in this locality,1 I was hopeful that I should
be able to increase the number during the past summer. Unfortu-
nately, pressure of work during fine weather, and the heavy rainfall
when it was possible to steal away from business, have frustrated
these bright hopes ; consequently, I have been able to make during
1891 but few additions to the list of species previously observed.
My attention has generally been confined during the past two years
to the marshes bordering the Thames upon either side of the river.
I have collected upon many occasions at Beckton, over the marshes
at Rainham, Purfleet, Grays, Thurrock, and Tilbury as far as Low
Street Station upon the Tilbury and Southend Railway. I have not
yet paid attention to the land shells of the Essex Marshes, but I hope
to do so in the future.
Parts of the marshes in Kent and Essex are somewhat incon-
venient to travel over, particularly after wet or foggy weather, when
the roads are rendered almost impassable by thick tenacious mud,
and the coarse grass, reaching to the knee, is saturated with moisture.
They are also intersected with numerous wide, deep, and in many
cases swift running dykes or drains, frequently involving the neces-
sity of a jump to avoid a detour of several miles. These ditches are
connected with the Thames in many places by drains and sluices,
and the river overflowing occasionally at high tides, the water in
them is more or less brackish. On the other hand these ditches are
interesting to the naturalist, being the abode of numerous aquatic
animals and plants ; in many places the dykes literally teem with
Mollusca, and with Microscopic Algae and Infusorian life. And
although the pernicious effects of the refuse from manufactories, and
particularly of the London Sewage, have done much to annihilate the
1 At the reading of the paper Mr. Jenkins exhibited a complete series of all the species and
varieties mentioned, and also presented an almost perfect series to the museum of the Club.—Ed.