64. The Shell-Collector’s Handbook. 
VALVATA PISCINALIS, MULLER. 
SHELL globular, thin, light horn-coloured, very finely 
spiral-striate, and marked with some obscure concentric 
lines ; whorls five to six, rounded, the body whorl being 
very large ; spire obtuse, compressed ; mouth circular, with 
a complete peristome; umbilicus deep; operculum 
greyish-white, circular. Length of shell } inch; width; inch. 
Animal yellowish-grey, with slightly apparent milk-white 
specks. 
Habitat. Bottom of shallow muddy streams, on marsh 
lands, or on aquatic plants in ditches and canals. 
v. depressa (C. Pfr.) : Spire more depressed ; umbilicus 
larger. (= V. depressa, C. Pfeiffer, Deutsch Moll. 1, p. 100, 
pl. i1., fig. 33.) 
v. subcylindrica (Jeff.) : Shell having the spire more 
produced and flattened at the top; umbilicus small. 
GENE,,.vol. 1., p. 72): 
v. acuminata (Jeff.): Shell having the spire still more 
produced, and ending in rather a sharp point. (B. C. 
. voli. p. 73). 
v. pusilla (Mull.): Shell smaller with stronger striz, 
and with four to four and a half whorls (= Nerita pusilla 
Mull., Verm Hist. i, p. 171.) 
v. albina (Taylor): Shell white or whitish. 
m. sinistrorsum (Jeff.): Spire reversed. 
VALVATA CRISTATA, MULLER. 
SHELL flatly-coiled, pale horn-coloured, striate trans- 
versely ; upper surface slightly concave; under surface 
umbilicate so as to expose the interior convolutions ; 
whorls five, the last being very large; mouth circular, 
and with a continuous margin; operculum round, slightly 
transparent, of a reddish horn-colour. Diameter of shell 
roth inch. Animal dark grey or brown, slate-coloured 
underneath, and with a few black specks on its upper part. 
Habitat.—Lakes, ponds, canals, and ditches. 
