THE LAND AND FRESHWATER MOLLUSCA OF SUSSEX.
By the Editor.
(Concluded from p. 126.)
II. AQUATIC MOLLUSCA.
BIVALVES (CONCHIFERA).
Order Lamellibranchiata.[1]
Fam. Sphæriidæ.
Sphærium[2] corneum. The Horn-coloured Sphærium.— Generally distributed and common in ponds, ditches and slow streams. The only species of the genus at present identified at Rathara, Chichester (J) and Eastbourne (G).
Sphærium rivicola. The Brook-haunting Sphærium.—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 Aruudel. 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.
Sphærium lacustre. The Lake-dwelling Sphærium.—This shell may be found in abundance in the Great Pond at Halting, 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 anv 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 Cambridge Philosophical Society' for 1832, and is full of valuable and interesting information. Some curious details of the habits of Sphærium lacustre, communicated by Dr. Lukis, of Guernsey, are
