124 MANUAL OF THE MOLLTJSCA. 



SIGARETUS (Adans.), Lamarck. 



Syn., cryptostoma, Bl. Stomatia, Browne. 



Type, S. haliotoides. PL VIII., tig. 4. 



Shell, striated ; ear-shaped ; spire minute ; aperture very wide, oblique 

 (not pearly). Operculum minute, horny, suh-spiral. 



The flat species are entirely concealed by the mantle when living ; the 

 convex shells only partially, and they have a yellowish epidermis. The ante- 

 rior foot lobe (mentum) is enormously developed, 



Distr., 26 sp. W. Indies, India, China, Peru. 



Fossil, 10 sp. Eocene . Brit., France, S. America. 



Sub-genus, naticina, Gray. N. papilla, pi. VIII., fig. j$. Shell ventricose, 

 thin, perforated. W. Indies, .Red Sea, China, N. Australia, Tasmania. 

 Eocene, Paris. 



LAMELLARIA, Montagu. 



Etym., lamella, a thin plate. 



Syn., marsenia, Leach. Coriocella, Bl. 



Type, L. perspicua. PL VIII., fig. 6. 



Shell ear-shaped; thin, pellucid, fragile; spire very small; aperture 

 large, patulous ; inner lip receding. No operc. 



Animal much larger than the shell, which is entirely concealed by the 

 reflected margins of the mantle ; mantle non-retractile, notched in front ; eyes 

 , at the outer bases of the tentacles. Lingual uncini 3, similar ; or one very 

 large. 



Distr., 5 sp. Norway, Brit., Medit., New Zealand, Philippines. 



Fossil, 2 sp. Miocene . Brit. (Crag.) 

 NARICA, Recluz. 



Syn., vanicoro, Quoy. Merria, Gray. Leucotis, Sw. 



Type, N. cancellata. PL VIII., fig. 8. 



Shell thin, white, with a velvety epidermis ; ribbed irregularly, and spi- 

 rally striated; axis perforated. Operc. very small, thin. 



Animal, eyes at the outer base of the tentacles; foot with wing-like lobes. 



Distr., 6 sp. W. Indies, Nicobar, Vanikoro, Pacific. 



Fossil, 4 sp. Gault (D'Orb.) Brit., France. 

 VELUTINA, Fleming. 



Etym., velutinus, velvety (from vellus, a fleece). 



Type, V. Isevigata. PL VIII., fig. 7- 



Shell thin ; with a velvety epidermis ; spire small ; suture deep ; ap 

 very large, rounded ; peristome continuous, thin. No operc. 



Animal with a large oblong foot ; margin of the mantle developed all 

 round, and more or less reflected over the shell; gills 2; head broad; tentacles 

 subulate, blunt, far apart ; eyes on prominences at their outer bases, 

 vorous. Lingual dentition like trivia (fig. 15, B.). 





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