36 CARDIAL. 



Cardium Pennantii, Reeve, Conch. Iconica, Cardium, pi. 9, f. 48. 

 „ vitellinum, Reeve, Conch. Iconica, Cardium, pi. 7, f. 37. 



The shape of the C. norvegicum is oblique and liable to 

 great modification, ranging from broadly obovate and sub- 

 ventrieose to subtriangular and tumid. The valves are 

 very inequilateral, solid, opaque, and rather glossy, of a 

 pale flesh- colour, spotted or subradiatingly speckled with a 

 deeper tint of the same hue, and covered with an olivaceous 

 drab or fawn-coloured epidermis, often becoming yellow 

 near the margin. The surface is radiated with very 

 narrow obsolete ribs, which gradually vanish in front, and 

 cease upon the hinder dorsal area, which is but very mode- 

 rately flattened. The ventral margin, which is but little 

 rounded in the middle, is well arcuated on each side, and 

 ascends rather the more obliquely and fully in front. The 

 anterior side, which is very considerably the lesser one, has 

 its extremity rounded both above and below, with the 

 front margin curving in an almost uninterrupted sweep from 

 the ventral, so that the dorsal edge is only distinguishable 

 by its greater straightness. The hinder dorsal margin, 

 which is the more elevated, and whose slope is moderate 

 and straightish, unites with the very oblique and but little 

 convex posterior edge without any angulation. The hinder 

 side is also rounded, and very projecting at the lower corner. 

 The ligament is large and prominent ; the umbones are nar- 

 row and projecting ; and the beaks are acute and much in- 

 flected, hardly leaning to either side. There is no decided 

 lunule, but instead of it a somewhat undefined lanceolate 

 flattened surface, which in the young is usually elevated, 

 and in the fry is coloured with crimson. The obsolete 

 umbonal ridge is devoid of all angularity. The interior is 

 whitish or pale flesh-colour, and the ventral margin is 

 coarsely dentated. The lateral teeth are rather approxi- 



