VONCHIFERA. 495 
ANATINA, Lamarck. Lantern-shell. 
Type, A, rostrata, Pl. XXIII., Fig. 7. (Anatinus, pertain- 
ing to a duck.) 
Synonyms, Laternula, Bolten MS. Auriscalpium, Muhlf. 
Osteodesma, Blainville. Cyathodonta (undulata), Conrad ? West 
America. 
Shell oblong, ventricose, sub-equivalve, thin and translucent, 
posterior side attenuated and gaping ; umbones fissured, directed 
backwards, supported internally by an oblique plate; hinge 
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. 
Sub-genera. Periploma (inequivalyis), Schum. ‘‘ Spoon- 
hinge” of Petiver; oval, inequivalve, left valve deepest; pos- 
terior side very short and couleneted: Distribution, West Indies, 
South America. 
Cochlodesma, Couthouy. OC. pretenue, Pl. XXIII, Fig. 8., 
(Bontia, Leach MS. Ligula, Mont., part.) Oblong, compressed, 
thin, slightly inequivalve ; ambones fissured ; cartilage processes 
prominent, ossicle minute; pallial sinus deep. Animal witha 
broad, compressed foot; siphons long, slender, divided through- 
out; gills one oneach 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.) Distribution, 2 species. United States, 
Britain, Mediterranean. Jossil, Pliocene, Sicily. 
Cercomya, Agassiz. C. undulata, Sowerby. (—Rhynchomya, 
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. Europe. 
Turacta (Leach), Blainyille. 
Synonyms, Odoncinetus, Costa. Corimya, Agassiz. Rupicola 
(concentrica), Bellevue. } 
