276 BRISTOL LAND AND FRESH-WATER MOLLUSCA. 



Var. i. radiata. G. Jeff. 



(*) Kennet and Avon Canal. 

 Var. ii. ventricosa. C. Pfeiffer. 



(*) Kennet and Avon Canal. 



Pamily III. — Dreissenid^. 



Genus 1. Dreissena. Tan Beneden. 

 1. D. polymorpha. Pallas. 



In the Docks at Bristol (T. G. P.) 1862, in the Avon, 

 and in the (*) Kennet and Avon Canal (W. W. S.) 



CLASS, GASTEEOPODA. 



Order I. — Pectinibranchiata. 



Family I.— Keritid^. 



Genus 1. Neritina. Lamarck. 



1. N. fluviatilis. Linne. 



Common throughout the district (W. 'W. S.), near 

 Baptist Mills, rare; Biislington, common, (T. G. P.) 

 1863; (-'") in the river at Stapleton, Keynsham 

 (J. & F. H.) 1874. 



Family II. — Paludinid^. 



Genus 1. Paludina. Lamarck. 



2. P. vivipera. Linne. 



Kare in the pond near Henbuiy and at Brislington 

 (T. G. P.) 1863; one specimen in the Brick-ponds 

 below Cook's Folly (E. C. W.), in the river at 

 Keynsham (J. &. F. H.), {;-•) in the Frome 

 (W. W. S.) 



Genus 2. BytJmiia. Gray. 

 1. B. tentaculata. Linne. 



Eare in the ditches at Shirehampton (T. G. P.) 1864, 

 (E. C. W.) 1874; in the river at Stapleton, stream 

 at Clevedon, ^N'ailsea, and Keynsham (J. & F. H.) 



