253 



Rounded-subtrigonal, solid, ruther inequivalve, nearly equila- 

 teral, ventricose, of a glossy ycUowisli white, or pale rose-colour, 

 nearly smooth, or marked in fresh specimens with distant striulse 

 towards the extremely arched ventral margin ; dorsal edges nearly 

 straight and strongly sloping on either side ; posterior side atten- 

 uated, almost beaked, and obtusely acuminated at the extremity ; 

 ligament extremely narrow and sunken ; umbones tumid ; beaks 

 distinct, prominent, and incurved ; fold distinct ; umboual ridge 

 almost obsolete ; inside usually yellow or rose-coloured at the um- 

 bones ; a small lunule ; teeth as in Nux. 



Isle of Aimaa, South Seas, and Isle of Burias, Pliili])pines. 



Is closely aUied to Nux, Piuguis and Casta, but of a stouter 

 texture even in the youngest individuals. The ligamental edge 

 being nearly straight, easily separates it from Phiguis, where it is 

 decidedly convex. 



57. Tellina casta (pi. Ivi. f, 9,) Hanley, Zool, Proc. 1844. 



T. testa obovali, tenuissima, subinsequivalvi, subinsequilaterali, 

 peUucida, convexa, nitida, extus intusque Candida, laevigata ; mar- 

 gine ventrali maxune arcuato ; dorsali utrinque subrecto, subajqua- 

 liter satisque dechvi; extremitate postica angusta, biangulata; 

 Hgamento angustissimo, subinfosso; natibus acutis; fiexura ven- 

 traH costaque umbonah distinctis ; dentibus ut in Nme. 



Oboval, extremely thin, shghtly inequivalve, nearly equilateral, 

 convex, glossy, pellucid, wliite, smooth ; ventral margin extremely 

 arcuated ; the dorsal on either side nearly straight, moderately and 

 nearly equally sloping ; beaks acute ; fold and umbonal ridge dis- 

 tinct ; posterior extremity narrow and biangulated ; Ligament ex- 

 tremely narrow and scarcely, if at all, projecting ; teeth as in Nux. 



Singapore. 



Bears some resem blance to Nux, but the shape is less broad, 

 the ventral edge decidedly arcuated, the dorsal edges less convex 

 and shorter, and the umbones colourless. 



58. Tellina balaustina (pi. Ivi. f. 10.) Lin. Svs. 1119. Poh. 

 Test. Sic. vol. i. 1. 14. f. 17. ; Lam. 2nd ed. vol. vi.^p. 209 ; Pliil. 

 En. Mol. Sic. vol. i. p. 25 ; Hani. Des. Cat. p. 72. sup. t. 9. f. 17 ; 

 Lucina balaustina, Payr. Cat. Cors. t. 1. f. 21, 22. 



T. testa obovata, aut suborbiculari, sohdiuscula, convexa, niti- 

 diuscula, albo-flavescente, radiis angustis rubris ornata, sublajvigata, 

 nonnunquam lineis elevatis concentrice striata; margine ventrali 

 arcuato ; dorsali utrinque convexo aut convexiuscido, satisque de- 



Q 



