which water flows. Specimens, however, have been procured from mud thrown out of a ditch in the level of the Arun between Burpham and Arundel.—B. It may sometimes be found on the submerged leaves of the yellow water lily, Nuphar lutea. This is the only freshwater species of the genus to be found in this country, although there are several marine forms which are also met with in brackish water.
Fam. Paludinidæ.
Paludina vivipara. Common Marsh-shell.—Occurs in the Arun.—B. I cannot help thinking that I have observed it in the ditches of the Pevensey level, and in the marsh-drains between Siddlesham and Selsea; but I have traversed so many marshes in different parts of the country that 1 may be mistaken as to these particular localities. I remember to have noticed this shell as common enough in some of the fen dykes of Cambridgeshire. Mr. W. Jeffery has recently informed me that Paludina vivipara occurs at Wisboro' Green, and that during the summer of 1877 he found it plentifully in a small stream which supplies a portion of the Wey and Arun Canal.—H.
Bythinia tentaculata. The Tentacled Bythinia.—Mr. Gwyn Jeffreys has pointed out that, although the derivation of the word Bythinia would imply that these mollusks inhabit deeper water than others of the same family, such is not the case. They generally frequent small streams, canals, shallow ponds and ditches, where they lay their eggs in three long rows on stones, as well as on the stalks and leaves of water-plants. In appearance the shell is not unlike a miniature Paludina, but the animal is oviparous instead of ovo-viviparous, and sessile-eyed instead of stalk-eyed. It is abundant in still stagnant ditches in the levels of all the Sussex rivers.
Bythinia Leachii. Leach's Bythinia.—Of rarer occurrence. Has been met with in a few of the ditches of Henfield level, and at Eastbourne.—B. Mr. Unwin includes it under the name ventricosa, Gray, as occurring at Lewes in ditches by the side of Kingston Road.
Fam. Valvatidæ.
Valvata piscinalis. Common Valve-shell.—In the ditches of Henfield level and at Eastbourne.—B. Very common in ditches
