274 BEISTOL LAND AST) FRESH-WATER MOLLUSCA. 



CLASS, LAMELLIBRANCHIATA. 

 Family I. — Sph^riid^. 



Genus 1: SphcBrium. Scopoli. 



1. S. cornea, L. (Cyclas cornea. Forbes and Hanley.) 



Not uncommon throughout the district. (•'') In the 

 river at Stapleton (T. G. P. and J. & F. H.;, 

 Shirehampton (E. W.), Keynsham, Kailsea, Cleve- 

 don (J. & F. H.). 



Yar. i. flavescens. Macgillivray. 

 Clevedon (L. C. J.) 



Yar. ii. nucleus. Studer. 

 (*) Clevedon. 



Yar. iv. Pisidioides. Gray. 



In the Avon (\V. W. S.) 



2. S. rivicola. Leach (Cyclas rivicola. Lamarck.) 



In the river at Stapleton (F. G. P.) 1862, (J. & F. H.) 

 1874 ; Keynsham (J. & F. H.) 



3. S. ovale. Ferussac. (Cyclas ovalis. Fer.) 



Kennet Canal (W. W. S.) 



4. S. lacastre. Miiller. (Cyclas caliculata. Forb. and 



Hani.) 



Clifton, in ponds (T. G. P.), pond near Horfieid, 

 pond on Downs, Keynsham, in stream (J. & F. H.) 



Genus 2. Pisidium. C. Pfeiffer. 



1. P. amnicum. Miiller. 



In the river at Stapleton (F. G. P.) 1862, Horfield 

 (W. W. S.), Clevedon and :N'ailsea (J. & F. H.) 



2. P. fontinale. Draparnaud. 



Stapleton (W. W. S.) 



