jeffery: the mollusca of western SUSSEX. 309 



Neritina fluviatilis. Last summer (1881) I found this shell 

 plentifully in the Arun, a few miles above the town of 

 Arundel, on chalk and stones at low water, for the tide 

 affects the height of the river thus far. The specimens 

 found were all of small size and more or less blackish 

 in colour (probably from incrustation) and showing no 

 markings, but some that I have kept living have, in a 

 considerable portion of new growth of the shell since 

 they were obtained, revealed the beautifully tessellated 

 markings commonly indicated in descriptions of it. 



Paludina vivipara. The only recorded locality for this shell 

 is the River Arun (Borrer in Zoologist, 1878). I found it 

 numerous at Wisbro' Green in 1877 in a ditch supplying 

 theWey and Arun Canal. It probably came from the Wey. 



Bythinia tentaculata. Common in most clear streams, 

 ponds and ditches. 



Valvata piscinaiis. Of frequent occurrence in such situations 

 as the last named, but generally in deeper water. In 

 May, 1868, I took about 350 shells from the stomach 

 of a large eel, nearly all of which belonged to this 

 species, but amongst them were a few Planorbis coin- 

 planatus and one Bythinia tentaculata. The variety 

 subcylindrica has occurred to me. 



V. cristata. Amongst weeds in ponds and ditches. No doubt 

 often overlooked from its resemblance at first sight to 

 young specimens of Planorbis. 



Planorbis nit id us, Fairly common. The alUed species, P. 

 lineatns, has not turned up in this dirtrict, though said 

 to be found sparingly in the eastern part of the county. 



P. nautileus. Found in a small pond at Chidham, without the 

 extremely elevated ridges which occur in the variety 



