286 CARDIID.E. 



8. C. edu'le *, Linne. 



C. edide, Linn. Syst. Nat. p. 1124 ; F. & H. ii. p. 15, pi. xxxii. f. 1-4, and 

 (animal) pi. N. f. 5. 



Body subglobose, thick, opaque white : mantle pale yellow ; 

 edges fringed with short white filaments, corresponding with 

 the ribs of the shell : tithes short, conical, separate at their 

 bases and divergent, whitish, pale yellow, or reddish -brown, 

 and sometimes speckled with black; the incurrent tube is 

 larger than the other, and has its orifice encircled with 10 

 long white cirri, besides two or three shorter ones between 

 each ; the excurrent tube has a plain orifice, and is provided 

 with a distinct retractile tubular valve ; the orifice of each 

 tube is bordered by a dark or red-brown line, and the sides of 

 both are clothed with curly white filaments, as well as part of 

 the mantle, as in other species of Cardium : gills suboval, pale 

 brown, finely pectinated ; upper pair much the smaller : palps 

 longish, pointed, flat, somewhat triangular, red-brown, smooth 

 on the outer and pectinated on the inner surface : foot long, 

 and lancet-shaped at the point, proportionally smaller than in 

 other species, varying in colour from opaque white to pale 

 yellow or brown, often of a deeper hue towards the extremity. 



Shell triangularly rhomboidal, convex, deeper behind, 

 somewhat compressed towards the margins, and especially at 

 the sides, very solid and opaque, of a dull hue: sculpture, 

 24-28 flattish ribs, more or less crested with straight trans- 

 verse plates, which are stronger and more developed at the 

 sides ; there are also some extremely fine and microscopical 

 longitudinal and transverse strire, which cover the whole sur- 

 face, making it appear partially shagreened ; furrows rather 

 narrow and slight, without punctures : colour whitish, or yel- 

 lowish, sometimes light reddish-brown, with a faint prismatic 

 lustre, marked transversely in the young by zigzag and irre- 

 gular streaks of purplish -brown : epidermis thin, fibrous, yel- 

 lowish-brown, usually rubbed off except round the edges: 

 margins gently curved but occasionally nearly straight in 

 front, rounded on the anterior side, obliquely truncate and 

 wedge-shaped on the posterior side ; on the upper part of this 

 side the margin forms an obtuse angle with the dorsal line, 

 which slopes a little : beaks very small, contiguous and con- 

 sequently often worn by the attrition, considerably incurved ; 



* Edible. 



