208 NATICID A. 
sea; usually, however, they are found living on stones near low- 
water. 
VELUTELLA, Gray. Shell thin, flexible, pellucid, smooth, mem- 
branaceous ; spire somewhat elevated ; mouth oblong, columella 
flexuous. JV. flexilis, Mont. (Ixiv, 86). 
[LIMNERIA, H. and A. Adams. (Morvillia, Gray.) Shell semi- 
globose, with wide expanded aperture, sometimes extending pos- 
teriorly beyond the apex; inner lip oblique, reflexed posteriorly, 
straight and acute anteriorly. V. zonata, Gould (Ixiii, 64, 65), 
which has been referred to the pulmoniferous genus Otina, is a 
typical species. | 
LEPTONOTIS, Conrad. Differs from Velutina in the remarkable 
expansion of the outer lip, and the distance of the apex from 
the margin. V. expansa, Whitfield (Ixiv, 68, 69). Eocene; 
Alabama. 
AMPLOSTOMA, Stoliczka. Subovate, thin, spire short; whorls 
few, the last large, ventricose, produced in front, widely exca- 
vated at base; aperture elongately ovate, subangulated, pillar- 
lip smooth, outer lip dilated and expanded at the margin; 
surface nearly smooth. Cretaceous; So. India, Europe. A. 
auriforme, Stoliczka (1xiv, 85). 
PuLatyostoMa, Conrad. 
Distr.—P. Niagarensis, Hall (lxiv, 74). Niagara group, New 
York. 
Shell subglobose ; spire short; aperture very large, suborbic- 
ular, dilated; labrum joining the body-whorl at right-angles to 
the axis of the shell. 
STROPHOSTYLUS, Hall. Shell subglobose or ovoid-globose; spire 
small, with a large, ventricose body-whorl; outer lip thin, not 
reflected (sometimes slightly expanded); columella twisted or 
spirally grooved within, not reflected ; umbilicus none; aperture 
somewhat round-ovate or transversely broad-oval. Fossil. Lower 
Helderberg. S. obtusus, Hall (Ixiv, 75). In this the columella 
is said to be twisted or spirally grooved within, whilst in Platy- 
ostoma the columellar lip is simply thickened. 
on1ostoMA, Mun.-Chal., 1876. Umbilicus’ moderate, circum- 
scribed by a carina; whorls sometimes partially free. O. Bar- 
randet, Mun.-Chal. Devonian. 
[tysis, Gabb (p. 112), may perhaps be related to Velutina. | 
LAMELLARIA, Montagu. 
EHtym.—Lamella, a thin plate. 
Syn. (Larval form).—Brownia, d’Orb. (B. Candei, d’Orb., 
Ixxxvii, 8,9). Calcarella, Souleyet (C. spinosa, Soul., xx, 51). 
Jasonilla, Macdonald. Echinospira, Krohn (2. diaphana, Kr., 
xx, 49, 50). 
