60 [ GO^GRYLl A— DITHYRA. 20. 



longitudinal raised striae : beaks prominent, not quite central : the 

 teeth in one valve obscure. 



bidentata. MoNTACUTA testd ovatd l(Bvi, dente altera obliquo cochleariformi. 



Shell oval smooth, with one of the teeth oblique and spoon- 

 shaped. 

 Mya bidentata Montagu, Test. Brit, p. 44, tab. 26, fig. 5. 



Linn. Trans, viii. p. 41. 



Turton, Brit. Fauna, p. 147. 



Pennant, Brit. Zool. iv. p. 166. 



Wood, Conch, p. 99. 



Dillwyn, Descript. Catal. p. 45. 



Turton, Conch. Diet. p. 102. 

 Mus. nost. Fine sand, and in the back of old oyster-shells. 



Shell hardly the eighth of an inch long, rather produced at one 

 end, whitish but not glossy, and frequently covered with a rough 

 coat : b'eaks near the broader end. 



ferrugittosa. MoNTACUTA testd oblongd, transversim substriatd, dente altera incurvo 

 ^' cochleariformi. 



Shell oblong, slightly striate transversely, with one of the teeth in- 

 curved and spoon-shaped. 

 Mya ferruginosa. Montagu, Suppl. p. 22, tab. 26, fig. 2. 

 Pennant, Brit. Zool. iv. p. 167. 

 Wood, Conch, p. 100. 

 Dillwyn, Descript. Catal. p. 46. 

 Turton, Conch. Diet. p. 102. 



