Mollusca of the Tai-Hu. 
309 
Length of shell 3-5 mm. Greatest breadth of shell 2 mm. Length of aperture i 
mm. Breadth of aperture 075 mm. 
The species is related to 5. monilifeva, Benson, but the shell is stouter and prob- 
ably shorter when complete, its aperture is smaller and relatively broader and its 
sculpture more distinct. 
Type-specimen. M. 11305/2. Zool. Survey of India {Ind. Mus.). 
Locality. Bottom of Tai-Hu (Great Lake), Kiangsu Province, China. 
The species is abundant on a bottom of bare mud in from 2 to 3 metres of water. 
Genus Pseudovivipara, gen. nov. 
Shell large, thin, resembling that of Vivipara but more elongate, oblong, conical, 
umbilicate, with the aperture large and ovate, with the collumellar lip thickened but 
the outer lip sharp, with the surface ornamented with prominent spiral ridges. 
Fig. 3. — Mouth of shell and operculum of Pseudovivipara hypocrites, sp. nov. 
A, mouth of shell ; B, external view of operculum ; C, internal view of operculum ; D, operculum in profile. 
Operculum calcareous, thick, large, concentric, covered with a thick horny epider- 
mis externally and with concentric striae on the external surface, internally convex 
with a narrow flattened margin, almost smooth, with obscure vermicular sculpturing. 
Animal resembling that of Bithynia, with a stout proboscis and a branched nenis, 
but with degenerate eyes. 
Radula with a pair of denticulations at each side of the base of the central tooth 
and with a lobular process at the outer margin of the marginal teeth. 
Type-species. — Pseudovivipara hypocrites, sp. nov. 
Distribution. Tai-Hu, Kiangsu and (?) Hainan. 
Although I describe Pseudovivipara hypocrites as a new genus and species, I am 
by no means sure that the shell of another phase has not already been figured by both 
Heude and Kobelt under the names Paludina boettgeri and Vivipara boettgeri, Mollendorf . 
