CARDIUM. 281 



6. C. fascia'tum *, Montagu. 



C. fasciatum, Mont. Test. Brit. Suppl. p. 30 ; F. & H. ii. p. 25, pi. xxxii. 

 f. 5, and (animal) pi. N. f. 4. 



Body suborbicular, flake-white : mantle plain-edged : tubes 

 usually not much produced, of the same length, and united, 

 each encircled with ten simple white cirri, and fringed with 

 longer filaments of the same colour : gills pale brown : foot 

 long, narrow, subcylindrical, or finger-shaped, and (contrary 

 to what it is in most other species of Cardium) hyaline. 



Shell obliquely triangular, convex but not very gibbous, 

 compressed towards the front, rather thin, but usually opaque, 

 not glossy: sculpture, 25 or 26 ribs, which are remarkably 

 flattened in front and compressed at each end of the shell ; 

 they are smooth in front, but are more or less covered on the 

 anterior side with obliquely transverse blunt plates, and on 

 the posterior side with short conical tubercles or prickles ; 

 furrows extremely narrow and slight, for the most part im- 

 pressed with numerous and minute circular punctures : colour 

 yellowish-white, with sometimes a tinge of red or pink near 

 the beaks, and frequently variegated by interrupted reddish- 

 brown bands, which are more conspicuous on the posterior 

 side : epidermis very slight, fibrous, yellowish-brown : margins 

 rounded on the anterior side, with an oblique slope to the 

 front, which is also (but more bluntly) rounded, more or less 

 elongated and wedge-shaped on the posterior side, with a 

 blunt angle running from the beaks ; on this side there is a 

 greater or less degree of truncature ; dorsal margin short : 

 heahs very small, not contiguous, inclining towards the ante- 

 rior side, but not so excentrically placed as in C. exiguum ; 

 beneath the beaks is a distinct but not deep lunule-shaped 

 depression : ligament rather long, cylindrical, narrow, greenish- 

 brown, occasionally continued on the anterior side : hinge-line 

 curved : hinge-plate thin and narrow, slightly reflected, some- 

 times stained with purplish-brown, occupying not one-fourth 

 of the circumference : teeth as in C. exiguum, but they are very 

 much slighter: inside glossy, frequently of an orange colour in 

 the middle and marked with reddish-brown streaks, fluted 

 more than in many other species, by reason of the shell being 

 thinner and the deposit from the mantle being more slight : 

 pallial scar scarcelv perceptible : muscular scars indistinct. 

 L. 0-5. B. 0-5. 



* Marked with bands. 



