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 yth, l8gi.\ 



T N bringing before the Essex Field Club the following account of 

 the MoUusca 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," 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 

 1 89 1 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 

 MoUusca, 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 



I 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.- Eu. 



