TELLINA. 301 



tion is subangulated below, but rounded off at the tip ; the 

 hinder dorsal edge is straight, and unites itself in an almost 

 uninterrupted line with the convex and very obliquely 

 sloping posterior margin. The umbones project but little ; 

 the beaks are very small, and almost directly inflected ; the 

 umbonal ridge is almost, but not quite, obsolete ; and the 

 ligament is large, elongated, and prominent. The interior 

 is coloured similarly to the exterior ; the teeth are very 

 small, and the hinge of the right valve exhibits an approx- 

 imate lateral in addition to, and immediately preceding, the 

 primary teeth. 



The average size of the full grown shell is nearly one 

 inch in length, and five- eighths of an inch in breadth. 



The animal, respecting which we have ample notes by 

 Mr. Clark and sketches by JNIr. Alder, is subtriangular 

 and very much compressed. Its mantle is open throughout 

 in front, and finely fringed at its edges. The siphonal 

 tubes are long and slender, separate through their whole 

 length, both somewhat curving upwards, often extended to 

 equal lengths, or having one or other alternately the longer, 

 most frequently the branchial being the shorter. The foot 

 is large, broad at the base, rather long, linguiform, and not 

 very acutely pointed. The branchiae consist of a single 

 large triangular leaf, on each side divided by a line into 

 two parts and finely pectinated. On each side of the 

 mouth there is a pair of long, rather narrow, pointed, 

 labial palps, smooth on their outsides and pectinated very 

 strongly within. The colour of the animal is yellowish 

 white. The tubes are nearly hyaline, and the branchiai 

 light bi'own. 



This is one of our commonest and prettiest bivalves. It 

 occurs in abundance on most of our sandy shores all round 

 Britain and Ireland ; so generally, indeed, that to cite lo- 



