7 
forms a welcome addition to a genus possessing so few species as 
that of Mya. Its distinct radiating strie occupying all but the pos- 
terior surface (which is roughened by concentric sublamellar wrin- 
kles), prevent the possibility of its being confounded with any other 
species, except the cancellata of Conrad. But the coarse transverse 
wrinkles which cover the entire surface of that shell are totally 
wanting in ours, whilst its radiating striz are few, indistinct, and by 
no means its prominent characteristic. 
The anterior attenuation is caused by the sloping upwards of the 
ventral edge. The tooth closely resembles that of arenaria, but is 
more oblique. 
