circe. 323 



ridges, of a somewhat irregular width, the interstices or 

 furrows being very narrow and slightly impressed ; the surface 

 is also covered with minute and irregular intermediate stria? : 

 colour from milk-white to rich purple, through all the shades 

 of j^ellow, brown, and red, often variegated or relieved by 

 diagonal streaks or rays of some one of those tints, and inter- 

 spersed with spots, or lineated in a zigzag pattern ; a common 

 arrangement of these varied hues consists of two streaks of a 

 darker or lighter reddish-brown radiating from the beaks at 

 an acute angle, one towards each side, and resembling an in- 

 verted V ; the colouring is so diversified, that it is almost im- 

 possible to describe it : epidermis semitransparent, like a coat 

 of varnish : margins semicircular in front and at both sides, 

 for at least half of the circumference, straight on the upper 

 part of the anterior side below the beaks, and sloping either 

 abruptly or with a gentle curve on the dorsal side to the pos- 

 terior angle: beaks regularly but not much recurved : lunule 

 not deep, denned by an impressed line : corselet slight : liga- 

 ment short, horncolour ; half of it is visible outside, and the 

 base rests on a groove excavated within the dorsal margin : 

 hinge-line rounded : hinge-plate thick, and somewhat flexuous : 

 teeth, as in the description of the genus ; the two cardinals in 

 the right valve on the anterior side are shorter and thicker 

 than the other on the posterior side, which is laminar and 

 nearly parallel to the dorsal line ; in the left valve the middle 

 cardinal is the shortest and thickest, that on the anterior side 

 is much smaller than the rest, and the tooth on the posterior 

 side (which is double) corresponds with the laminar tooth in 

 the right valve ; laterals short and strong, the inside tooth in 

 the left valve being considerably smaller than the other: 

 inside polished and slightly nacreous, sometimes tinged with 

 neshcolour ; margin bevelled and smooth, but occasionally in 

 the left valve it is indistinctly crenulated: scars not very 

 distinct. L. 0*55. B. 0*6. 



Var. triangularis. Shell acutely triangular, in consequence 

 of the beaks being more prominent and the sides more truncate. 

 Venus triangularis, Mont. Test. Brit. p. 577, tab. 17. f. 3. 



Habitat : All our coasts, on a sandy or nullipore 

 bottom, in 5-85 fathoms. The variety lias been found 

 by Montagu and myself in Falmouth Harbour. This 

 species occurs in the Red and Coralline Crag. Sars 



