438 Zoology. 



Paludestrina confusa, Frau. Common from N. France to 

 Corsica. Jeffrey's habitat, " between Greenwich and Wool- 

 wich " has long been obsolete. Found by me in 1891 in a small 

 puddle near Erith. Mr. S. Kennard found an example living in 

 the same ditch, 1895. The P. anatina of Oulton Broad ie, 

 however, now said to be the same. It was originally known as 

 Hydrobia similis (H.). 



Paludestrina jenkinsi, Smith. Swarms in brackish ditches from 

 Arsenal Wall at Plumstead to Gravesend. Originally found and 

 named from here. See articles referred to above. Since has 

 spread up the Cray into quite fresh-water. I received specimens 

 from Crayford in 1905 from Mr. Birts, junr. It is now found in 

 many parts of the coast of England. In 1883 it was common 

 as high as Greenwich, and no doubt may spread upwards as 

 the river becomes purer (H.). 



Paludestrina ventrosa. Mont. Brackish ditches, more brackish than 

 P. jenkinsi prefers, especially about Gravesend. Originally 

 far more common in England than P. jenkinsi (H.). 



Paludestrina stagnalis, Bas. (Hydrobia ulvae of older authors). 

 Nr. Gravesend, 1902 (K.) ; sparingly in brackish ditches near 

 Greenhithe (H.). 



Bithynia tentaculata Linne. Common, Plumstead Marsh (H.) ; 

 Ravensbourne (L.) ; Southend (R.A.A.) ; Bromley, scarce (S.K.). 



Bithynia leachii, Shep. Not rare in ditches in Plumstead Marsh > 

 1892 (H.). 



Vivipara contecta, Miller. Beckenham (S.K.). 



Valvata piscinalis, Miiller. Common in Ravensbourne, 1906 (L.) ; 

 Chislehurst, Southend (R.A.A.). 



Valvata cristata, Miiller. Erith, 1892 (H,) ; Ravensbourne, scarce, 

 1904 (L.). 



Assemania gray ana, Leach. Estuarine. From Erith downwards, 

 1892 (H.); Gravesend, 1903 (C.) ; Medway at Cuxton, 1904 (L.); 

 originally described from this district (S.K.). 



Pomatias elegans, Miiller. Bostall and elsewhere where there is. 

 chalk, 1892 (H.) ; Shoreham and Swanley, 1896 (C.) ; Bromley, 

 common (S.K.) ; Farnborough, 1906 (L.) ; Green Street Green, 

 Orpington (R.A.A.). 



Neritina fluviatilis, Linne. River Darenth at Eynsford, 1902 (L.). 



Anodonta cygnaea, Linne. Common in ditches. Plumstead (H.) 

 Ravensbourne (L.) ; Bromley, uncommon (S.K.). 



