coiircEirEEA. 485 



separate, orifices cirrated, brancliial cirri dendritic ; foot com- 

 pressed, broadly lanceolate ; gills large, unequal ; palpi small. 



Suh-genus. Anapa, Gray. A. Smithii, PL XXI., Pig. 17. 

 Umbones anterior, sij)honal inflection obsolete. 



Ceronia, Gray. Lateral teeth marked with coarse oblique 

 striae. 



? Davila, Gray. Laterals unequal ; anterior teeth small and 

 erect. 



Distribution, 31 species. West Indies, Mediterranean, Crimea, 

 India, New Zealand, Chili ; sands at low water. 



Fossil, 7 species, Neocomian — . United States, Europe, 

 {Donacilla, D'Orbigny.) 



Eryilia, Turton. Lentil-shell. 



Etymology, ervilia, diminutive of ervum, the bitter-vetch. 



Ttjpe, E. nitens, PL XXL, Fig. 18. 



Shell minute, oval, close ; cartilage in a central pit ; right 

 valve with a single prominent tooth in front and an obscure 

 tooth behind ; left valve with 2 obscure teeth ; no lateral teeth ; 

 pallial sinus deep. 



Distrihution, 2 species. West Indies, Britain, Canaries, 

 Mediterranean, Eed Sea. — 50 fathoms. 



DoiS'AX, L. Wedge-shell. 



Example, D. denticulatus, PL XXL, Pig. 19. 



Etymology , donax, sl sea-fish. (Pliny.) 



Synonyms, Chione, Scop. Cuneus, Da Costa. Capisterium, 

 Meuschen.* Latona and Hecuba, Schum. Egeria, Lea (not 

 Eoissy). 



Shell trigonal, wedge-like, closed ; front produced, rounded ; 

 posterior side short, straight ; margins usually crenulated ; 

 hinge- teeth 2.2 ; laterals 1 — 1 in each valve ; ligament external, 

 prominent ; pallial sinus deep, horizontal. 



Animal with the mantle fringed ; siphons short and thick, 

 diverging, anal orifice denticulated, branchial with pinnate 

 cirri ; foot very large, pointed, sharp-edged, projected quite in 

 front ; gills ample, recumbent, outer shortest ; palpi small, 

 pointed. 



Distrihution, 68 species. Norway, Baltic, — Black Sea, all 

 tropical seas. In sands near low-water mark ( — 8 fathoms) 

 buried an inch or two beneath the surface. 



Fossil, 45 species. Carb. — . United States, Europe. 



* Meuschen was a Dutch auctioneer ; the nanaes occur in his " sale catalogues." 

 JdiotiB imposuere norriina absurda. Linnaeus. 



