246 CO^GRYLIA—DITHYRA. 55. 



Shell an inch and a quarter long, and nearly three inches broad, 

 narrow oval, covered with a yellowish-green skin, a little flexuous 

 at the anterior side and slightly contracted at the margin near the 

 middle ,• inside perlaceous, with often a fawn-colored tint. 



ovata. 

 3. 



Mysca testa ovatd, antici attenuatd, margine subarcuato, umhonibus 



corrugatis. 

 Shell oval, tapering to the anterior end, with the margin slightly 



arcuated, and the beaks wrinkled. 

 Mya ovata. Linn. Trans, viii. p. 39. 



Wood, Conch, p. 105, tab. 19, fig. 5. 



Dilliryn, Descript. Catal. p. 50. 



Turton, Conch. Diet. p. 106. 

 Mya ovalis. Montagu, Test. Brit. p. 563. 



Mya depressa. Donovan, British Shells, iii. tab 101. 



Musculus angustior. Lister, Conch, tab. 147, fig. 2. 

 Mus, nost. From the Avon and Froome, Wiltshire. 



Shell an inch and a half long, and two inches and a half broad, 

 covered with a brownish-green skin, much longer in proportion to 

 its breadth than the two last, rather depressed, often radiate : the 

 margin is mostly arched a little outwardly, sometimes contracted in 

 the middle, and sometimes with the anterior end slightly falcate; but 

 may be distinguished by its more regularly oval shape. 



solida. Mysca testa crassd solidd subcylindricd, antic^ conico-acuminatd, 

 umbonibus corrugatis. 

 Shell thick solid and somewhat cylindrical, conically tapering to a 

 point at the anterior end, and the beaks wrinkled. 



