266 RISSOIDA. 
In L. minula the rostrum is rather long, the tentacles very 
slightly tapering, blunt at the end, foot rounded behind. 
Hyprosia, Hartmann. 
Syn.—Paludinella, Lovén. Peringia, Paladilhe. 
Distr.—W orld-wide, brackish water. H. ulve, Pennant 
(Ixxii, 54). 
Shell ovate or elongated, smooth, subperforate ; spire conic ; 
whorls flat; apex acute; aperture ovate; inner lip not thickened. 
Operculum corneous. 
Rostrum rather long, tentacles somewhat tapering, but blunt 
at the extremity. Foot somewhat pointed behind. 
EMMERIcIA, Brusina. 
Distr.—Living, 2 sp. Adriatic Region. /. patula, Brum. 
Shell small, conoidal, rimate, smooth, shining, spire elevated ; 
aperture patulous; peristome subcontinuous, inner lip adnate, 
the outer lip sinuate, wide, reflected. Operculum corneous, ovate, 
paucispiral, nucleus excentric. 
TOURNOUERIA, Brusina. Peristome inferiorly evased, simple. 
1 recent, several tertiary species. Europe. 
STALIOLA, Brusina, 1870. Peristome with a strong exterior 
marginal rib. Tertiary; Europe. 1 recent sp. 
NystiA, Tournouer, 1869. (Forbesia, Nyst.) Aperture oblique, 
exteriorly swollen, spire truncate. Tertiary; Europe. £. 
microstoma, Desh. 
BirHyNe.LaA, Moquin-Tandon. 
Syn.—VWeachia, Risso. Subulina, Troschel. Paludinella, Frau- 
enfeld. Microna, Ziegler. Thermhydrobia, Paulucci. Frauen- 
feldia, Clessin. 
Distr.—Fresh water, Europe, America, including California. 
B. viridis, Moquin-Tandon (1xxii, 55, 56). 
Shell elongated-ovate, usually somewhat pupiform, imperforate, 
or simply rimate; apex obtuse; aperture oval or rounded ;_peri- 
treme continuous, outer lip slightly thickened. Operculum 
corneous, nucleus moderately large, not very close to the basal 
margin. 
Tentacles tapering, blunt at the tip; foot rather narrow, 
rounded behind ; verge bifid. 
STIMPSONIA, Clessin. Proposed for the North American species, 
which differ from the European type in dentition. 
VITRELLA, Clessin. (Bythiospeum, Bourg., 1882.) Shell small, 
thin, without sculpture; peritreme continuous, sharp. Operculum 
paucispiral. Animal blind. Inhabits caves and streams in 
Europe. 15 sp. Bb. pellucida, Clessin (1xxii, 57). 
MOITESSIERIA, Bourg. Shell inoperculate (7), diaphanous, crys- 
talline, very fragile, microscopic, cylindrical, elongated; form of 
