MANUAL OF THE MOLLUSCA. 



Family VI. — Littoeintdjb.* 



The genera are — 



Littobina, including Tectaria, Modulus, and Ri sella ; 

 Lacuna, and 



Fossaiujs, Philippi (p. 253). 



Synonyms, Phasianema, Wood ; Maravignia, Arados. 



Shell perforated, sculptured ; inner lip thin ; aperture semi- 

 lunate ; operculum not spiral. 



Animal with two frontal lobes between the tentacles. 



Distribution, 43 species, including species of the sub-genera. 

 Mediterranean and tropical seas. 



Fossil, 4 species. Miocene. Europe. 



Sub-genera, Conradia, Coutliouyia, Citlma, Oottoina. 



Fossarina, Adams, differs from Fossarus in the curved inner 

 lip and circular aperture. 2 species. Australia. 



Isapis, H. and A. Adams. Columella with a plait ; in I. 

 anomala it is almost obsolete. 4 species. Jamaica and Mazat- 

 Lxn. 



Lacunella, Deshayes, 1864. 



Etymology, diminutive of Lacuna (see p. 255). 



Type, L. depressa, Desh. Eocene. Paris. 



Shell ovate, thin, pellucid, shining, very depressed ; apex 

 obtuse ; aperture large, dilated ; outer lip thin, reflected ; colu- 

 mella narrow, thin, concave, grooved, with the base perforated. 



FRaullnta, Mayer, 1864. 



Dedicated to M. Eaulin. 



Type, Odostomia alligata, Deshayes. Eocene. Paris basin. 



Shell turbinated, oval-oblong, moderately thick, spirally sul- 

 cated ; whorls rapidly increasing, convex ; last whorl very 

 large ; aperture large, angulated posteriorly, expanded in front ; 

 columella broad, arcuate, flattened, with a prominent tuber- 

 culous tooth. 



Eucycltjs, E. Deslongchamps, 1860. 



Etymology, eu-huklos, circling, in allusion to the numerous 

 plications or rings of the spire and base. 



Examples, Turbo ornatus, Sow. ; T. capitaneus, Mlinst. 



* See p. 250. 

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