32 BIVALVES. TELLINA. 



being broad at one end, and gradually tapering to the 

 other; in some cases so much so, that the pointed termi- 

 nation of the shell forms a perfect beak or proboscis, as 

 in the T. rostrata, T. virgata, &c. Others, on the con- 

 trary, are more of an orbicular, or spherical form, as the 

 T. scobitina, &c. and some again, as the T. radiata, &c. 

 are nearly allied to species of the Solen genus, with which 

 (from their near resemblance) they are sometimes con- 

 founded; however, from the general propensity of all 

 Tellinae to terminate in a more or less acute beak, much 

 inaccuracy cannot well be committed. At the same time, 

 the hinge of the Tellina will remove any doubts that may 

 have originated from the simple observance of the exte- 

 rior ; for it is usually furnished with three teeth, the mid- 

 dle one often cleft ; the lateral teeth are most commonly 

 smooth : the interior margin rarely, if ever, crenulated. 



The outside of the shells is surprisingly varied, some 

 being perfectly smooth and polished, whilst others are 

 covered with minute striae and undulations. In some in- 

 stances the whole surface is beset with coarse imbrica- 

 tions or scales; but the more elegant species of the Tel- 

 lina are chiefly remarkable for their beautiful radiations, 

 the colors of which are rarely to be equalled in any of 

 the other genera. 



As theTellin9e are most important among the Bivalves, 

 so the sources from whence they are derived, usually 

 abound in the different varieties they afiford. The Me- 

 diterranean, Adriatic, European and Northern Seas, and 

 the American and Atlantic Oceans produce a great num- 

 ber. The rivers, pools, ponds, and marshes of Europe and 

 America, supply only a few. The finest varieties are 

 found in the pearl fisheries of Ceylon. 



