• OOS-CSIFERA. 495 



Anatina, Lamarck. Lantern- sliell. 



Type, A. rostrata, PI. XXIII., Pig. 1. {Anatinus, pertain- 

 ing to a duck.) 



Synonyms, Laternula, Bolten MS. Auriscalpium, Muklf. 

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

 America. 



Shell oblong, yentricose, sub^equivalve, thin and translucent, 

 posterior side attenuated and gaping ; umbones fissured, directed 

 backwards, supported internally by an oblique plate ; binge 

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

 in front with a transverse ossicle; pallial 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 very long and narrow ; pedal opening minute, 

 foot very small, compressed. 



Distribution, 20 species. India, Philippines, New Zealand, 

 West America. 



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

 Europe. 



Suh-genera. Periploma (inequivalvis), Schum. " Spoon- 

 hinge" of Petiver; oval, inequivalve, left valve deepest; pos- 

 terior side very short and contracted. Distrihuiion, West Indies, 

 South America. 



Cochlodesma, Couthouy. C. prsetenue, PI. XXIII. , Pig. 8, 

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

 thin, slightly inequivalve ; umbones fissured ; cartilage processes 

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

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

 out ; gills one on each side, deeply plaited, divided 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.) JDistrihution, 2 species. United States, 

 Britain, Mediterranean. Fossil, Pliocene, Sicily. 



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

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

 posteriorly ; sides concentrically furrowed, umbones fissured, 

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

 Oolite — Neocomian. Europe. 



Theacia (Leach), Blainville^ 



Synonyms, Odoncinetus, Costa. Corimya, Agassiz. Eupiccla 

 (concentrica\ Bellevue. 



