HELICIDA, 35 
quently hirsute. H. personata, Lam. (xciv, 37). 4 sp. United 
States, Europe. 
MESODON, Kaf., 1831. (Patera, Albers, 1850.) Shell umbili- 
cated or imperforate, depressed globose, striate or costulate ; 
last whorl deflected near the aperture ; peristome reflected, white ; 
parietal wall usually obliquely dentate. Shell usually corneous, 
without bands. MM. albolabris, Say (xciv, 38. H. multilineata, 
Say, has revolving brown bands, which sometimes coalesce into 
a uniform brown. 20 sp. United States. 
Ulostoma, Albers, 1850. Shell large, umbilicated, globosely 
depressed ; aperture semicircular; lip reflected, tuberculately 
toothed at the base ; sometimes with also a small parietal tooth. 
H. profunda, Say (xciv, 39). 2sp. United States. 
STROBILA, Morse, 1864. Shell minute, umbilicated, globosely 
conic or depressed, obliquely and coarsely striated, smoother 
below ; whorls 5-6, the last globose ; aperture lunately rounded, 
peristome thickened and reflected ; the parietal wall and base of 
last whorl each with two or more revolving lamelle. Animal 
with thick, bulbous tentacles, and large eyes. H. labyrinthica, 
Say (xciv, 18’. 4 sp. United States, Mexico, West Indies. 
THELIDOMUS, Swainson, 1840. Shell imperforate or very rarely 
umbilicated, solid, globosely depressed; spire short, obtuse ; 
whorls four or five, the last contracted and deflected at the 
aperture, gibbous, obtusely angular on the periphery ; aperture 
transversely oval; peristome very thick, reflected, the extremi- 
ties connected by a wide callus, basal portion of lip often 
callously tuberculate or denticulate within. 21 sp. West Indies. 
Hi. ( Pachystoma) Guantanamensis, Poey (xcvi, 77). 
Letocheila, Albers, 1850. (Leiostoma, Swainson, 1840.) Shell 
imperforate, subglobular, rather solid; spire short, obtuse, whorls 
three-and-a-half, the last very large, ventricose; aperture large, 
obliquely rounded ; columella arcuated, widely callous; lip cal- 
lously thickened. A. Jamaicensis, Chemn. (xevi, 78). Jamaica. 
Pachystoma, Albers, 1850. (Otala, Mirch, 1852.) Imperforate, 
very rarely narrowly umbilicate, solid, depressly globose; spire 
short, obtuse ; whorls 4-5, the last protracted at the aperture, 
gibbous; sometimes obtusely angulated; peristome thick, the 
margins callously connected, base callous or denticulate. H. 
auricoma, Fer. Mostly Cuban. 
Eurycratera, Beck, 1837. (Parthena, Albers, 1850, part.) 
Shell umbilicated or imperforate, rather thin, ventricose, obliquely 
oval; whorls few, very rapidly increasing, the last greatly de- 
veloped ; aperture oblong, oblique; peristome simple or slightly 
expanded below, the lips united by a thin callus; columellar lip 
narrowly reflected. H. obliterata, Fer.:xevi, 81). 20sp. Hayti. 
Coryda, Albers, 1850. Shell imperforate, globosely conic or 
depressed ; whorls five and a half, the last anteriorly deflected, 
