46 CO^CHYUS.~DITHYRA. 14. 



Shell oblong, angular and truncate at the anterior end, with, a 

 notch on the teeth at the broader end. 



Tab. nost. 4, fig. 3. The young shell. 

 Mya pubescens. Montagu, Test. Brit. p. 40. 



Turton, Conch. Diet. p. 99, fig. 35. 

 Mya declivis. Linn. Trans, viii. p. 36, Dorset Catal. p. 27, 



tab. 4, fig. 6. 

 Wood, Conch, p. 93, tab. 18, fig. 3. 

 Mus. nost. Torbay and Plymouth. 



Shell when full grown two inches and a half long and three 

 and a half broad, oblong, much flatter than the Anatina convexa, 

 rough, striate transversely, brownish white : beaks nearly central, 

 with the points not opposite, but crossing each other at the tips: 

 teeth projecting and running obliquely to the anterior side, with 

 a cavity or notch behind and small erect denticle : inside with an 

 oblique rib from the tooth towards the truncated end. 



We have been fortunate enough to procure the intermediate 

 sizes of this species, by which we are enabled to clear up all diffi- 

 culties with respect to the young of the present shell ; and the 

 Mya declivis of Montagu. 



This has the teeth oblique, as may be ob»ervGd in our plate; 

 and the Mya declivis has the teeth projecting inwards and oval, 

 as may be seen in Montagu's plate 1, fig. 2. 



tiuncata. Ajj^tj^a testd convexd cuneatd, latere postico truncato, umho- 

 nibus subterminalihus. 

 Shell convex wedge-shaped, truncate at the hinder end, with the 

 beaks nearly terminal. 



