27 



Genus II.— Lyonsla, Turt. 

 Lyonsia norvegica, Cheni. 



Lyonsia norvegica, v elongata, Gray. 



Family XVIII.— ANATINIDyC, D'Orb. 



Genus Thracia, Leach, 

 ThRACIA PR/ETENUIS, Flilf. 



Thracia pra3tenuis, v curta, /ejf, 

 Thracia papyracea, Foli. 



Thracia papyracea, v gracilis, Jeff. 



Thracia papyracea, v villosiuscula, Macg. 

 Thracia pubescens, Fult. 

 Thracia convexa, IV. IVood. 

 Thracia distorta, Mo7if. 



Thracia distorta, v truncata. Turf. 



Family XIX.— CORBULID/E, Fkm. 



Genus I. — Poromya, Forbes. 

 PoROMYA granulata, Nyst &> West. 



Genus II.— Neaera, Gray. 

 Ne^era abbreviata, Forb. 

 Neaera. costellat a, Des. 



Neaera costellata, v lactea, Jej^. 

 Ne^ra cuspidata, OHvi. 



Nea?ra cuspidata, v curta,y6;^^ 

 Nei^ra cuspidata, v cinerea, y^. 



Genus III.— Corbula, Brttg. 



CORBULA GIBBA, OHvt. 



Corbula gibba, v rosea, Bro. 



Family XX.—U\\D/E,F/em. 



Genus Mya, L. 

 Mya arenaria, L. 



Mya arenaria, v lata, /. Sow. 

 Mya truncata, L. 



Mya truncata, v abbreviata, Jeff. 

 Mya Binghami, Turt. 



Mya Binghami, v elongata, /ejff. 



