THE DISTRIBUTION OF BRITISH NON- 

 MARINE MOLLUSCS. 



I. HAND LIST FOR ESSEX. 



In accordance with an annonncemsnt made in the Journal, 

 it is proposed to pubhsh Hand Lists of tlie Non-Marine Molluscs 

 occurring in the various Counties of the British Isles. In order 

 to make such lists really complete, and of greater value, there 

 should be included in them the names of extinct and other 

 species, found fossil in the Counties to which they refer. There 

 are, however, many difficulties in tlie way of domg this. In the 

 first place, very few of the published Lists of Fossil Shells are 

 reliable. Again, the labour of working through these lists with 

 the specimens which have been preserved, is greater than 

 anyone who has not participated in it would believe, and as 

 there are but two or three workers in this difficult branch of the 

 subject, the progress made is correspondingly small. 



Under these circumstances it is possible that all fossil 

 records may not be included in every list, though as the Essex 

 Post-Pliocene Mollusca have been recently Avorked out in great 

 detail, they are included in the present one. 



Author ilies for the following List in ivhose papers reference to previous 

 K'orh on the subject liiill he found. 



1897. Wilfred Mark Webb.—" The Non-Marine Molluscs 

 of Essex." Essex Nat., Vol. X. (1897) pages 

 27-48, and 65-81. 



1897. A. S. Kennard and B. B. Woodward, with con- 

 tributions by Wilfred Mark Webb. — " The 

 Post-Pliocene Non-Marine Mollusca of Essex." 

 Essex Nat., Vol. X. (1897) pages 87-109. 



N.B. — The Editor of the " Essex NaturaUst " — William Cole— has since 

 pointed out that specimens of Dreissensia polymorplui, from the Lea, are in 

 the Epping Forest Museum. Essex Nat., vol. x., p. 189. 



