CONCHYLIA— D/THYi?^. 52. 237 



Turton, Linn. Syst. iv. p. 287. 

 Chemnitz, viii. p. 106, tab. 78, fig. 713. 

 Dillwyn, Descript. Catal. p. 296. 

 Turton, Conch. Diet. p. 5, fig. 42, 43, 44. 

 Lister, Conch, tab. 211, fig. 46. 

 Mus, nost. Found on Teignmouth beach. 



Shell nearly an inch and a quarter long, and an inch broad, con- 

 vex, of a blackish horn-color, inflected and smooth at the sides, 

 longitudinally striate on the disk, with the beak of the upper valve 

 elongated curved and pointed. 



52. m^Qmk— LAMARCK. 



Testa ineequivalvis ovato-orbicularis, depressiuscula, fixa ; valvd utrdque 

 disco centrali orbiculato. Discus valves superioris medio suhma- 

 millatus, inferioris rimd transversa divisus. Cardo indistinctus- 

 Ligamentum internum. 



Shell inequivalve, roundish-oval, rather flat, and fixed ; each valve 

 furnished with an orbicular central disk. The disk of the upper 

 valve papillary near the middle, of the under valve divided by a 

 transverse cleft. Hinge indistinct. Ligament internal, 



