180 TELLINA. TELLEN. 
pi. 13. f. 2— Donovan , pi. 96 : — Wood, pi. 46. f. 3— Dorset 
Cat. pi. 7- f- 2. 
Shell somewhat globular, inclining to a triangular shape, 
thin, transparent, pale horn-color or yellowish-white, ge¬ 
nerally covered with a dark skin or an extraneous coat, 
often bright yellow’ round the front margin, iincly striate 
concentrically, with a single large deep transverse groove, 
which is sometimes near the margin, sometimes about the 
middle, and often wanting $ inside smooth glossy, blucish- 
white : beaks prominent, obtuse, central: hinge with the 
primary teeth very minute; lateral ones remote and promi¬ 
nent, double in one of the valves ; length three eighths of 
an inch 5 breadth half an inch. 
Variety. Double the size, and without the groove. 
The single transverse groove appears' to be rather a 
mark of annotination than a determinate specific character. 
In the young shell it is wanting ; as it increases in age it 
appears close to the frontal margin; and in old shells it ap¬ 
proaches pretty near to the hinge. 
Mr. Wood has unfortunately translated the Linnean cha¬ 
racter, “ sulco transversali,” by the words “transversely 
grooved.” And Mr. Dillwyn seems to have fallen into the 
same mistake. 
31. Tellina lacustris. Lake Tellen . 
Wood , pi. 47. f. 5. 
Shell somewhat rhombic, very thin, transparent, smooth 
or obscurely striate transversely, flattisli, especially round 
the front margin, pale horn-color or covered with a dark 
brown skin: beaks very obtuse, and so much projecting be¬ 
yond the margin as to give the shell a heart-shaped appear¬ 
ance when viewed sideways : hinge with a pkiin tooth in 
one valve, and a cloven one in the other: length three 
tenths of an inch ; breadth four tenths. 
It differs from the last, in its flattened margin, projecting 
beaks, and rhombic shape. 
In slow and stagnant waters, v. v. 
32. Tellina polygona. Polygonal Tellen. 
Montagu , pi. 28. f. 4. 
Shell somewhat orbicular, a little produced at the end, 
dirty 
