c-ONCHIFERA. 495 



Anatina, Lamarck. Lantern-shell. 



Type, A. rostrata, PI. XXIII. , Fig. Y. {Anatinus, pertain- 

 ing to a duck.) 



Synonyms, Laternula, Bolten MS. Auriscalpium, Muhlf. 

 Osteodesma, Blainville. Cyatliodonta (undulata), Conrad ? West 

 America. 



Shell oblong, yentricose, sub-eqniyalve, thin and translucent, 

 posterior side attenuated and gaping ; umbones fissured, directed 

 backwards, supported internally by an oblique plate ; hinga 

 with a spoon-shaped cartilage process in each yalye, furnished 

 in front with a transyerse ossicle ; pallia 1 sinus wide and 

 shallow. 



Animal with a closed mantle and long united siphons, clothed 

 with wrinkled epidermis ; gills one on each side, thick, deeply 

 plaited ; palpi yery long and narrow ; pedal opening minute, 

 foot yery small, compressed. 



Distribution, 20 species. India, Philippines, New Zealand 

 West America. 



Fossil, 50 species. Deyonian ? — Oolite — . United States, 

 Europe. 



Sub-genera. Periploma (inequiyalyis), Schum. *' Spoon- 

 hinge " of Petiyer ; oyal, inequiyalye, left yalye deepest ; pos- 

 terior side yery short and contracted. Distribution, West Indies, 

 South America. 



Cochlodesma, Couthouy. C. preetenue, PI. XXIII., Fig. 8., 

 (Bontia, Leach MS. Ligula, Mont., part.) Oblong, comjDressed, 

 thin, slightly inequiyalye ; umbones fissured ; cartilage processes 

 prominent, ossicle minute; pallial sinus deep. Animal with a 

 broad, compressed foot ; siphons long, slender, diyided through- 

 out ; gills one on each side, deeply plaited, diyided by an oblique 

 furrow into two parts, the dorsal portion being narrower, com- 

 posed of a single lamina only, and attached by its whole inner 

 surface. (Hancock.) Distribution, 2 species. United States, 

 Britain, Mediterranean. Fossil, Pliocene, Sicily. 



Cercomya, Agassiz. C. undulata, Sowerby. (=Ehynchomya, 

 Agassiz.) Shell yery thin, elongated, compressed, attenuated 

 posteriorly ; sides concentrically furrowed, umbones fissured, 

 posterior (cardinal) area more or less defined. Fossil, 12 species. 

 Oolite — Neocomian. Eui'ope. 



Thkacia (Leach), Blainyille. 



Synonyms, Odoncinetus, Costa. Corimya, Agassiz. Eupiccla 

 (concentrica^; Bellevue. 



