a2 HELICIDA. 
angulate, slightly descending in front; columella inclining, wide; 
aperture truncately ovate; peristome thickened, sometimes cal- 
lously tuberculated, shortly reflected, patulous, basal margin 
eallously dilated. H. imperator, Montf. (xevi, 84). 5sp. Cuba, 
Porto Rico. 
Dentellaria, Schum.,1817. (Lucidula, Cyclodoma, Swn., 1840.) 
Shell imperforate, very rarely umbilicated, solid, depressed or 
conical globose; spire obtuse; last whorl deflected in front, 
mostly angular at the periphery; aperture oblique or subhori- 
zontal, transverse; peristome thick, dentate or tuberculate within, 
its extremities joined by a heavy parietal callus. H. Josephine, 
Fer. (xev, 72). 18 sp. West Indies, South America. 
Pleurodonta, Fischer, 1807. (Caprinus, Montf., 1810. Lyros- 
toma, Morch, 1852. Lucernella, Swn., 1840.) Shell orbicular, 
conoidal or lenticular, imperforate, or umbilicus covered ; whorls 
five or six, flattened, the last carinated or angulated; aperture 
elliptical, oblique, nearly horizontal; peristome thick, subtrape- 
zoidal, the extremities joined by a thickened callus, lower lip 
dilated, reflected, dentate within, with opposite exterior pits. H. 
lucerna, Muller. H. soror, Fer. (xcvi, 85’). 35 sp. Jamaica. 
Labyrinthus, Beck, 1837. (Lyrostoma, Swn., 1840.) Shell 
umbilicated, depressed orbicular, convex above and below; 
whorls five or six, the last carinated, depressed at the aperture ; 
aperture nearly horizontal, auricular, grimacing, lamellated and 
dentate within; peristome thick, reflected, the extremities 
approaching, and continued subparallel into the umbilicus. H. 
labyrinthus, Chemn. (xevi, 86). 22 sp. Central and South 
America, 
Cepolis, Montfort, 1810. Shell umbilicated or partly covered, 
globosely depressed; whorls 45-5, the last suddenly deflected 
at the aperture, gibbous, scrobiculate or suleate, tuberculate or 
plicately callous within; aperture elongate-lunate, peristome 
more or less expanded, the basal margin dilated, reflected, dentate 
or callous. H.cepa,Mull. 9sp. Hayti, Porto Rico, Nicaragua, 
Java, China. 
Isomeria, Albers, 1850. Shell umbilicated, depressed orbic- 
ular; last whorl obtusely angulated on the periphery, rounded 
in front, deviating near the aperture, ventricose at base, and 
contracted around the umbilicus; aperture oblique, semioval, 
with two interior teeth, one at the periphery, the other upon the 
opposite parietal wall; peristome thickened, reflected. HH. oreas, 
Koch (xevi, 87). 23 sp. Northern South America. 
soLARopsIs, Beck, 1837. (Solarium, Spix, 1827. Ophiodermis, 
Agassiz, 1837.) Shell umbilicated, orbicularly depressed, 
flattened, conical above, convex below; last whorl obtusely cari- 
nated and peculiarly constricted at the periphery; aperture 
obliquely semilunar; peristome labiate, reflected ; columellar lip 
