236 MANUAL OF THE MOLTUSCA. 
Operculum, horny. 
Neverita, Risso. N. Alderi. Fig. 95. 
Lunatia, Gray. N. Ampullaria. Perforation simple; epider- 
mis dull, olivaceous. Northern seas. 
Globulus, J. Sby. (Ampulina, Deshayes not Bl.) N. Sigaretina. 
Pl. VIII., Fig. 2. Umbilicus narrow (rimate), lined by a thin 
callus. 
Fossil, Hocene. Britain, Paris. 
Polinices, Montfort (naticella, Guild.}, N. mammilla. Shell 
oblong; callus very large, filling the umbilicus. 
Cernina, Gray, N. fluctuata. Pl. VIII., Fig. 3. Globular, 
imperforate ; inner lip callous, covering part of the body-whorl. 
Naticella, Miller. 19 species. 
Fossil, Trias, §. Cassian. 
DESHAYESIA, Raulin 
Miocene, France. Some additional species have been found 
with a similar oblique aperture and corrugated inner lip. 
Baron Ryckholt has described a species (D. Raulini), from the 
Devonian, Belgium. The relation of the genus is uncertain. 
NATICELLA, Minster. 
This genus, abounding in the Trias of St. Cassian, has been 
referred to Natica by D’Orbigny. A characteristic species 
occurs in the green-sand of Blackdown, and has been named 
Natica carinata, J. Sby. (Narica, D’Orbigny.) It is exactly 
intermediate between Narica (p. 237) and /ossarus (p. 263), and 
appears to form with them a little group nearly related to 
Lacuna (p. 255). 
SIGARETUS (Adans.), Lamarck. 
Synonyms, Cryptostoma, Bl. Stomatia, Browne. 
Type, 8. haliotoides. Pl. VIII., Fig. 4. 
Shell striated ; ear-shaped ; spire minute : aperture very wide, 
oblique (not pearly) ; operculum minute, horny, sub-spiral. 
The flat species are entirely concealed by the mantle when 
living; the conyex shells only partially, and they have a 
yellowish epidermis. The anterior foot lobe (mentum) is enor- 
mously developed. . 
Distribution, 31 species. "West Indies, India, China, Peru. 
Fossil, 10 species. Hocene—. Britain, France, South America. 
Sub-genus. Naticina, Gray. N. papilla, Pl. VIII., Fig. 3. 
Shell ventricose, thin, perforated. West Indies, Red Sea, China, 
North Australia, Tasmania. Locene, Paris. 
