OF THE BECONTREE HUNDRED.
207
Family PALUDINIDAE.
Paludina vivipara, L. River Roding, Woodford Bridge to
Red Bridge, Wanstead ; common,—also var. unicolor.
Bythinia tentacula a. L. Ditches, Wanstead; ponds at
Carswell and Fern Hall, Barking Side; and grips of Roding
Meadows, St. Swithin's Farm; plentiful.
Bythinia leachii, Shepp. Ponds and ditches at Fern Hall
and St. Swithin's ; not common.
Family VALVATIDAE.
Valvata piscinalis, Muller. Ditto ; abundant.
Valvata cristata, Muller. In meadow grips and shore ditch
St. Swithin's, Barking Side; plentiful. The living animal of this
small operculated species, with its gills extended like a plume, is an
interesting and beautiful study.
Order PULMONOBRANCHIATA.
Family LIMNAEIDAE.
Planorbis nitidus, Muller. River Roding, near the old Mill ;
two specimens.
Planorbis nautileus, L. Pond at Carswell, Barking Side ;
not very plentiful.
Planorbis albus, Muller. Ponds and ditches, St. Swithin's ;
but not common.
Planorbis glaber, Jeffreys. Carswell Pond ; one specimen.
Planorbis spirorbis, Muller. In ponds, ditches, and grips
at Wanstead, Walthamstow, Barking Side, &c.; common every-
where.
Planorbis vortex, L. Ditto, ditto.
Planorbis carinatus, Mull. Ponds and ditches at St.
Swithin's Farm, forest pools at Whips Cross, and in the River Lea
at Temple Mills; but local and not so common as P. complanatus.
Planorbis complanatus, L. Ditto, and River Roding ;
common everywhere.
Planorbis corneus, L. Ponds and meadow grips at Barking
Side, Wanstead, Eastham, Leyton, &c.; abundant. A variety, dark
red in color and with the later whorls obliquely coiled round the
younger shell, was extremely common in the Forest Ponds at Whips
Cross a few years ago. The young shells are usually very hispid.