L61 
THE LAND AND FRESHWATER MOLLUSCA OF SUSSEX. 
By viz Epiror. 
(Concluded from p. 126.) 
II. AQUATIC MOLLUSCA. 
BIVALVES (CONCHIFERA). 
Order LAMELLIBRANCHIATA.* 
Fam. SPH#RIIDA. 
Spherium+ corneum. The Horn-coloured Spherium.—Gene- 
rally distributed and common in ponds, ditches and slow streams. 
The only species of the genus at present identified at Ratham, 
Chichester (J) and Eastbourne (G). 
_ Spherium rivicola. The Brook-haunting Spherium.—Mr. Borrer, 
writing under date 4th December, 1877, says:—“A brother of 
_mine has to-day shown-me some specimens of Cyclas rivicola, 
which he collected from the rejectamenta of the floods of the 
Arun, at Burpham, near Arundel. I never met with it myself, 
although I should quite have expected it, as the Arun and the 
Wey are connected by a canal, and the shell is abundant in the 
Wey, at all events about Guildford.” This species is not included 
in any other of the Sussex lists. 
Spherium lacustre. The Lake-dwelling Spherium.—This shell 
may be found in abundance in the Great Pond at Harting, near 
Petersfield, and in the streams issuing from it.—W. It occurs 
also in ponds at Cowfold (B), and is included in a list of Mollusca 
from the vicinity of Brighton (M). Although not mentioned in any 
other of the Sussex lists, it is probably generally distributed, and 
has been either overlooked, or perhaps, when encrusted with mud, 
confounded with some other species. 
_ The Rev. Leonard Jenyns, who has paid much attention to this 
group of freshwater bivalves, published a monograph of the British 
species, which will be found in the ‘Transactions of the Cam- 
bridge Philosophical Society’ for 1832, and is full of valuable and 
interesting information. Some curious details of the habits of 
Spherium lacustre, communicated by Dr. Lukis, of Guernsey, are 
* Having leaf-like gills. 
+ By many conchologists the name Cyclas is retained for this genus, 
Vg 
