CO^CHYUX—DITHYRA. 26. »7 



the inside from pale yellow to the richest purple: hinge with a 

 single cloven tooth in one valve, and a cavity on each side for 

 the reception of the two teeth of the opposite valve. 



Montagu considered this shell to be the young of the Solen 

 vespertinus, probably from not having met with the latter in its 

 various stages of growth. We have a complete series of the Solen 

 vespertinus, from less than a quarter of an inch to two and a half 

 in breadth, and are satisfied that this is very distinct, as may be 

 seen by comparing the figure above quoted, with the figure 10, of 

 the same plate. 



The Solen vespertinus, when of the same size is flatter, more 

 angular at the anterior end, of a paler color both inside and out- 

 side, with the rays of a pale violet : in the hinge are also two 

 teeth in each valve, one of them rather oblique and laminar ; the 

 transverse striae are stronger, with only a few very indistinct 

 longitudinal ones at one end in full grown shells. 



PsAMMOBiA testa ovato-oblnngd, striis transversis longitudi- costuiata. 

 nalihusque ininimus, latere antico costulis obliquis longitudi- 

 nalibus. 



Shell oval-oblong, with transverse striae and minute longitu- 

 dinal ones, and oblique longitudinal ribs at the anterior end. 



Tab. nost. 6, fig. 8. 



Mus. nost. Dredged in Torbay, and the Channel. 



Shell about half an inch long, and an inch broad, thin, slightly 

 angular at the anterior end where there are about twelve fine 

 oblique longitudinal ribs radiating from the hinge; finely striate 



V 



