222 Bulletin American Museum of Natural History [Vol. LIT 
Paludestrina erythrea (E. v. Martens) = Hydrobia erythrea E. v. MARTENS, 1858, 
Archiv f. Naturgesch., XXIV, 1, p. 186, Pl. v, fig. 11. Shores of the Red Sea. 
Paludestrina gabonensis (Morelet) = Hydrobia gabonensis MoRELET, 1885, Journ. 
de Conchyl., XX XIII, p. 30, Pl. 11, fig. 12. Ogowe River, Gaboon. This was said to 
have a corneous operculum and must therefore be one of the Amnicoline. 
Paludestrina schweinfurthi (Jickeli) =Hydrobia schweinfurthi JickeLi, 1874, 
Nov. Acta Ac. Nat. Cur. Dresden, XX XVII, 1, p. 250, Pl. v1, fig. 35. White Nile. 
The generic reference of this is somewhat dubious. 
Paludestrina tristis (Morelet) =Hydrobia tristis Moretnt, 1889, Journ. de 
Conchyl., XX XVII, p. 18, Pl. 11, fig. 4. Port Elizabeth, Cape Colony. We have 
examined specimens of this species and it appears not to be a typical Paludestrina, the 
central tooth of the radula having several basal denticles and the outer lip of the shell 
being slightly sinuous. The formula of denticles is 325, 7, 10, many. The basal 
denticles stand in an oblique row on each side, the outer one lowest and extremely 
minute. 
Paludestrina zwellendamensis (Kiister) =Paludina zwellendamensis KUstER, 
1852, in Martini and Chemnitz, ‘Syst. Conch. Cab., I, 21, Paludina,’ p. 53, Pl. x, 
figs. 19-20. Zoetendal Valley, Swellendam District, Cape Colony. 
Eussoia Preston, 1912, Proc. Zool. Soc. London, p. 192. This was described as a 
fluviatile snail, having the appearance of Assiminea, but without operculum. We 
have examined a cotype of the only species, Hussoia inopina Preston (1912, op. cit., 
p. 192, Pl. xxxt1, fig. 10. Banks of the Eusso Nyiro River, Kenya Colony) and can 
find but little difference with Paludestrina. We are inclined to believe that it belongs 
in Amnicoline. The specimens may have lost their thin, corneous operculum, after 
death, while the decayed animal remained in the shell. 
PoTAMOPYRGUs Stimpson 
Potamopyrgus Stimpson, 1865, American Journ. Conch., I, p. 53. Monotype: 
Amynicola corolla Gould. 
Patamopyrgus Pmre., 1887, ‘Catal. Conch. Samml.,’ I, p. 429. Misspelling of 
Potamopyrgus. | 
Pyrgophorus ANCEY, 1888, Bull. Soc. Malacol. France, V, pp. 188 and 192. Type 
by present designation: Pyrgulopsis spinosa Call and Pilsbry. 
With the exception of the species mentioned below and the British 
Hydrobia jenkinsi Smith, which appears to be a Potamopyrgus, the genus 
is restricted to South and Central America (northward to Texas), New 
Zealand, Tasmania, and Australia. Unlike Amnicolide generally, the 
young are born alive. 
Potamopyrgus ciliatus (Gould) =Amanicola ciliata Goutp, 1850, Proc. Boston 
Soc. Nat. Hist., III, p. 196. 
“Shell small, elongate, imperforate, brownish-green; spire acutely conic; 
whorls 6, subangulate, armed with a series of recurved spines on the angle, the last 
whorl acutely carinate at the periphery; aperture circular ; lip black. 
“Length 14, width % inch. Hab. Deea River, Liberia, on the muddy margins. 
Dr. Perkins.”’ | 
