180 TELLINA. TELLEN. 



pi. 13. f. 2 Donovan, pi. 96 Wood, pi. 46. f,3 Dorset 

 Cat. pi. 7. (.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, finely striate 

 concentrically, with a single large deep trans verseigroove, 

 which is sometimes near the margin, sometimes about the 

 middle, and often wanting ; inside smooth glossy, blueish- 

 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 j 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. DiUwyn seems to have fallen into the 

 same mistake. 



31. Tellina lacustr^^^e Tetten. 

 Wood, pi. 47. f. 5. ; 



Shell somewhat rhombic, very thin, transparent, smooth 

 or obscurely striate transversely, flattish, 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 plain 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. 



Jn 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, 



dir ty 



