114 CONCUYUX—DITHYRA. 28. 



In some specimens also we have remarked a small remote 

 tubercle on each side the hinge, like obscure lateral teeth. 



^?>X- Foved interna rectiusculd. 3-6. 

 The internal cavity nearly straight. 



alba. LuciNA testci ovbiculari coHvexd, sirils transversis regularibus 

 remotiusculis, valvd alterd bideniatd, altera unidentatd. 

 Shell orbicular convex, with rather remote regular transverse 

 striai, hinge with two teeth in one valve and one in the other. 

 Tab. nost. 7, fig. 6 and 7. 

 Mtts. nost. British Channel, and shores about Guernsea. 



Shell about three eighths of an inch in diameter; and differs 

 from the Lucina Leucoma, in being of a more regularly rounded 

 form, of a more glossy white, with the striae rather distant and 

 about half the size of the interstices between them, without the 

 deeper ridges or the least appearance of longitudinal lines, and 

 the internal cardinal cavity is narrow and nearly in a straight 

 direction. 



lotundata. LuciNA testd concexd Iteviiisctdd, margine subundato, valvis 

 bidentatis. 

 Shell convex and nearly smooth, a little undulate in the circum- 

 ference, with two teeth in each valve. 



Tab. nost. 7, fig. 3. 

 Tellina rotundala. Montagu, Test. Brit. p. 71, tab. 2, fig. 3. 

 Pennant, Brit. Zool. iv. p. 182. 

 Linn. Trans, viii. p. 56. 

 Turton, British Fauna, p. li\. 



