380 VENERID^. 



beautiful variety figured by Turton (so common in the 

 Adriatic), in which the pattern is composed of radiating 

 rows of smoke-coloured, irregularly-shaped spots (not a 

 little resembling the Chinese style of writing) upon a 

 ground of bluish-grey, is not of frequent occurrence upon 

 our coasts. The sculpture (which is coarser in our ex- 

 amples than in the majority of those we receive from the 

 Mediterranean) consists of most closely arranged and rather 

 wavy concentric sulci, decussated throughout by radiating 

 strise ; the latter are more crowded in the middle area 

 (where the concentric sulci often disappear or become faint- 

 er), are stronger and more remote in front, and behind the 

 umbonal slope lose all claim to be held as stria, forming 

 shallow interstitial grooves to the apparently radiating 

 rows of compressed bead-like prominences, which the in- 

 tersected sulci there present. The ventral margin is 

 moderately convex in the middle, and rises greatly at the 

 sides, particularly in front ; the declination, as well as 

 the convexity, of the hinder dorsal edge is very trifling ; 

 the front dorsal edge slopes almost rectilin early, and rather 

 profoundly, to about the middle of the narrow anterior 

 side, whose extremity is well rounded and rather attenu- 

 ated ; the hinder side is about twice as long as the other, 

 and has the appearance of being subtruncated at its ex- 

 tremity, from the posterior edge being but little convex, 

 and not greatly oblique ; the posterior termination is broad, 

 and almost biangulated, the lower angle being, however, 

 rounded off in the young (at which stage the angulation 

 in shells is always most apparent) ; the ligament is rather 

 large, yellowish brown, and not much elevated. The 

 lunule is not usually much depressed, and is frequently 

 only defined by its freedom from decussation ; its lips, too, 

 except in aged examples, are elevated, not sunken ; the 



