4 SOLENID.E. 



two-thirds cover the ventral or front part of the shell, and 

 radiate from the beak, the rest occupying the whole of the 

 posterior side, and diverging from an angle formed by a junc- 

 tion with the first-mentioned set of striae ; this angle varies 

 from acute to obtuse, according to the number of striaa ; the 

 anterior side is not thus striated ; the surface is also covered 

 with minute and crowded longitudinal stri* resembling those 

 observable in species of Psammobia : colour pale yellowish- 

 white : epidermis like oil-skin, yellowish with a brown tint in 

 aged specimens : marc/ins slightly incurved in front, obliquely 

 truncated with a rounded contour at each end, nearly straight 

 behind and parallel with the front, except in the middle, where 

 the beak forms a projection equal to the indentation on the 

 opposite side : beaks pointed and nearly straight : ligament 

 chrysalis- shaped, prominent, dark horncolour : hinge-line 

 straight : hinge-plate thick and strong, reflected over the 

 ligament and abruptly truncated at the posterior end : hinge 

 supported by a strong oblique shelf-like rib : teeth, in the right 

 valve two blunt cardinals curving upwards from below the 

 beak, the posterior being much larger than the other ; the 

 left valve has a similar cardinal on the anterior side, besides a 

 short, triangular and oblique lateral on the posterior side: 

 inside chalky- white, with a slightly nacreous gloss in some 

 parts, incipient pearls being occasionally formed on the 

 inner edge of the mantle ; margin blunt : pallial scar well 

 defined ; sinus oblong, and extending two-thirds across the 

 transverse diameter of the shell : muscular scars distinct ; an- 

 terior irregularly pear-shaped, posterior triangularly oval. 

 L.0-9. B.l-9. 



Var. oblonga. Shell narrower in proportion to its breadth. 



HABITAT : In sand, between low-water mark at spring 

 tides (Lukis), and various depths seawards, from 20 

 to 85 fathoms, on different parts of the coast from the 

 Shetland to the Channel Isles, but local ; more common 

 in Bantry Bay than elsewhere. Var. 1. Guernsey 

 (Lukis) ; Polkernow Cove, Cornwall (Miss Lavars) ; 

 Shetland (Barlee) . Believing it to be the Solen multi- 

 sir iatus of Scacchi, I find it recorded as a fossil from the 

 neighbourhood of Antwerp, and from Gravina in Apulia. 

 Lamarck and Brocchi appear to have mistaken a white 



