162 THE ZOOLOGIST. 
given by Mr. Gwyn Jeffreys, in his ‘ British Conchology’ (vol. 1., 
pp. 12—135). 
Pisidium amnicum. The River Pea-shell.— Formerly the 
species of this genus were all classed with Spherium, but, 
independently of their smaller size, they differ in the shape of 
their shells, which are not equilateral,—that is, the beak is 
situated near the shorter end,—and in having but one contractile 
tube or syphon, instead of two. The name Pisidium was bestowed 
from the gregarious habits of the species, individuals of which may 
often be found in considerable quantities, scattered about like peas. 
Pisidium amnicum is by no means uncommon in rivers and gently 
running streams, residing wholly at the bottom, and partly buried 
in the mud. In the parish of Harting it is widely distributed along 
the water-courses traversing the Down Park and the Nyewood 
meadows.—W. In the neighbourhood of Lewes, however, Mr. 
Unwin considers it somewhat rare, although he has found it in 
the Cut, and in the streams which empty themselves into the 
Ouse. In the vicinity of Brighton, also, it is not considered 
common.—M. 
Pisidium fontinale. The Stream Pea-shell.—Mr. Gwyn Jeffreys 
has described four varieties of this species, which have been 
catalogued by some conchologists as specifically distinct, under 
the names Henslowianum, pulchellum, pallidum and cinereum. 
Mr. Unwin has entered it in his Lewes list of Mollusca, under the 
name Henslowianum, and remarks that he has only met with two 
specimens. In the Brighton list it is included as P. pulchellum 
and marked ‘“‘rare.” Mr. Weaver has catalogued it, under the 
name cinereum, as a species inhabiting the streams in the East 
Harting district. It is reported to occur, also, in the vicinity of 
Eastbourne: —G. 
Pisidium pusillum. The Little Pea-shell.—In ditches in the 
levels of the Arun and the Adur, and in ponds at Cowfold amongst 
Lemna minor.—B. Occasionally amongst freshwater Alge@, with 
other minute species, in the vicinity of Lewes.—U. Under the 
name obiusale, Mr. Weaver has recorded it as tolerably plentiful 
in the parish of Harting in a shallow water-course in a meadow 
known as Pannell’s Hole, and Mr. W. Jeffery reports that it is 
found at Burton, near Petworth. It is recorded with doubt as 
occurring at Eastbourne (G), and noted as rare in the neigh- 
bourhood of Brighton (M). 
