404 TELLINIDJ5. 



dorsal margin on the anterior side long and sloping but not 

 curved, that on the posterior side being much shorter, diver- 

 ging from the other at considerably more than a right angle, 

 and nearly straight : beaks small, pointed, incurved, and 

 turned towards the posterior or ligamental side : ligament very 

 short, partly prominent, the lower half being imbedded in the 

 hinge-plate, norncolour : corsel t long, rather dee]), with thick- 

 ened and projecting edges ; hinge-line obtusely angular : hinge- 

 plate thick, much longer but narrower on the anterior than on 

 the posterior side, abruptly truncate at the end of the liga- 

 ment: teeth, in the right valve a triangular and eleven car- 

 dinal immediately below the beak, flanked on each Bide by a 

 longer and laminar cardinal, the anterior of which is set ob- 

 liquely and the posterior or larger one in a line with the liga- 

 ment ; laterals in this valve two on each side, receiving be- 

 tween each pair the single lateral of the opposite valve ; the left 

 valve has two diverging cardinals and an intermediate minute 

 tooth or denticle : the laterals (one on each side) in that valve 

 are short and sometimes tubercular: insick highly polished 

 and usually glossy, more or loss stained with violet, especially 

 on the posterior side; margin finely and regularly notched 

 from the anterior end to the ligament: the posterior dorsal 

 margin is more closely notched or crenulated, and the other 

 dorsal margin is quite smooth: pallial scar slight, with an 

 oval and rather small sinus: muscular scars strongly marked, 

 of an irregular shape. L. (Kb B. 1*1. 



Var. 1. turgida. Shell larger, ventricose, longer in propor- 

 tion to its breadth, and nearly lustreless except in the young. 

 L. 1. B. 16. 



Var. 2. nitida. Shell somewhat smaller than usual and 

 more convex, broader in proportion to its length, of a brilliant 

 lustre. 



Habitat : Largo sandy bays, from low-water mark 

 to a few fathoms within the Laminarian zone. Var. 1 . 

 Stornoway in the outer Hebrides (Barlee). Var. 2. 

 Dredged in 18 fathoms, ten miles off Shields (Da- 

 mon) ; and on the Dogger bank in 12-15 fathoms, 

 thirty miles from Scarborough (Leckenby) . This spe- 

 cies is fossil in the Belfast deposit (Milieu) j Wexford 

 (James); Ayr (Smith); Mod Tryfaen, Carnarvonshire, 



