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out, even as far down as Barnes and Putney : it seems to live 

 contentedly either in clear running water, or in the liquid mud 

 which does duty for water in the lower parts of the Thames. 

 Of the remainder of this division the shells of Barnes 

 Common are fairly typical, and here are found PI. lijieatus, 

 Walker, a curious little shell which has the interior separated 

 by plates into chambers something after the fashion of the 

 Nautilus. Also the little Vertigo antivertigo, Drap., and still 

 smaller Vertigo pygmeea, Drap., and even smaller than this the 

 tiny H. pygmcea, Drap., the smallest of our British Helices. 

 Farther down the river at Putney is found CL biplicata, 

 Mont., now the only British locality of the species, and when 

 built over or drained, as seems inevitable, it will probably 

 become extinct. Close by here is found P. roseum, Scholtz. 

 This shell has been recorded for Hastings by Mr. J. H. A. 

 Jenner; but the only other locality of recent date is Minster, 

 where it was first noticed by Mr. S. C. Cockerell. 



The North Kent Region. — This is merely a narrow strip 

 extending through Greenwich, Woolwich, Gravesend, and 

 Chatham. The distinctions, however, which warrant this 

 being classed as a separate division are mainly of a negative 

 character. The larger species of Planorbis found along the 

 Thames valley are mainly absent, but their place is taken by 

 small shells of the genus LimncBa, Pisidiiun, Valvata, etc. 

 Almost the only characteristic shell is Hydrobia similis, Drap., 

 a little shell not a genuine freshwater species, but it occurs in 

 muddy ditches and other places that are occasionally over- 

 flowed by the tide. With it is sometimes found Assiminea 

 graya7ta, Leach, another estuarine species, though more 

 marine in its habits than Hydrobia, 



The North-East Kent and Thanet Division. — This district 

 includes a strip extending from the coast line to the North 

 Downs, and from Sheppy through Whitstable, Heme Bay, 

 Margate, and Ramsgate, to Sandwich. It was undoubtedly 

 once a portion of the old Thames Valley ; and therefore it is 

 not surprising to find that the fauna bears a marked resem- 

 ,blance to that of the present valley, and that there are very 

 few distinct species. Assiviinea grayana, Leach, which first 

 appeared in the last division is here fairly common in brackish 

 water. Perhaps the most representative shell may be con- 



