92 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



"We are greatly indebted to Dr. 0. Boettger and Dr. Ewald Wiist 

 for kind assistance in determining this species. In a living state 

 we are able to record it from Harrogate, Yorkshire ; Knettishall, 

 Mendlesham, Suffolk ; whilst in a fossil state it is represented in 

 our collections from the Holocene of Knettishall, Suffolk ; Clifton 

 Hampden, Oxfordshire ; Staines, Middlesex ; Walthamstow, Chignal, 

 llford, Essex ; Greenhithe, Kent ; Westbury, Gloucestershire ; and 

 from the Pleistocene of Barnwell, Cambridgeshire ; Copford, Essex ; 

 and Swanscomb, Kent. There can be no doubt that it is a widely 

 distributed form in England, especially in the eastern counties, but we 

 have not as yet seen specimens from Wales, Ireland, or Scotland. 



The band formulae of the specimens of Helix nemoralis are — 



1 2 3 (4 5) ... ... ... ... 8 examples. 



(1 2) 3 (4 5) ... 6 



12 3 4 5 8 



1 3 (4 5) 2 



3 2 



10 3 4 5 2 ,, 



(2 3 4 5) 1 ,,. 



(12 3 4 5) 1 



In their general facies the examples of this species from Uxbridge 

 are very similar to those from the Lea alluvium at Walthamstow. 



Helicigona arhustorum, as usual, varies very much in size, the largest 

 measuring 20 X 22*5 mm., and the smallest 13 X 17 mm. A mature 

 sinistral example of this species, found and kindly given us by 

 Mr. Loydell, measures 15 X 17 mm., and is the only fossil reversed 

 specimen that we can trace, though one or two living examples have 

 been found in this country. 



Planorhis Strmmii is only represented by a single example, and that 

 may well be a derived specimen. 



We have ventured to apply the name of Planorhis leiicostoma, 

 Millet,^ to the shell which is generally called in those Islands 

 P. spirorbis, Linn., because it is not the latter form, though possibly 

 only an extreme variety thereof. 



Paludestrina ventrosa is represented by a single example, and is 

 an extremely interesting record. At the present time this species 

 is with us a brackish-water form, and in the Thames it is not found 

 far above Erith, but in Pleistocene times it was present in fresh 

 water, whilst on the Continent at the present day it frequents both 

 brackish and fresh waters. 



Speaking broadly, the shells from Uxbridge are a typical Thames 

 Holocene group, and are in all probability of Eoman or post- 

 Roman age. 



^ The name P. rotnndatus, Poiret, 1801, antedates this, and is by some authorities 

 considered to represent a synonym of Millet's species, but there is considerable 

 doubt as to what Poiret's species really was, and hence we have not adopted 

 the name. 



