314 



vex, dull whitish (internally pure white), covered by a thin ash- 

 coloured fugacious epidermis ; ventral margin more or less convex ; 

 front dorsal edge arched and slightly sloping, hinder one straight 

 and greatly sloping; posterior side short, subangulated below; 

 anterior extremity rounded ; beaks usually eroded ; ligament large 

 and jirominent ; fold almost obsolete ; one of the teeth bifurcate 

 (when the hinge is perfect, which is rarely the case) in each valve. 

 Boston, (Gould) ; Arctic Ocean. 



181. Tellina calcarea (pi. Ixii. f. 183.) Chemnitz, \o\.\\. 

 p. 140. f. 136 ; Dillwyn D. Cat. p. 93 ; Hani. Des. Cat. p.46. t.4. 

 f. 43 ; T. sordida, PJdl. Ab. und Bes. Conch, part 9. t. 5. f. 6. 



T. testa ovata aut subovata, solidiuscula, subinsequivalvi, con- 

 vexiuscula, insequilateraU, extus intusque albida, epidermide cine- 

 rascente induta, sublsevigata ; margine ventrali satis convexo, 

 postice accKnato; dorsali antice convexo et subdechvi, postice 

 declivi et subrecto ; latere antico longiore, ad extremitatem rotun- 

 dato ; postico obtuse cuneiformi ; natibus acutis, prominentibus ; 

 costa umbonali satis distincta; flexura ventrali subinconspicua ; 

 hgamento magno, prominulo ; dentibus parvis. 



More or less ovate, moderately firm, very slightly inequivalve, 

 tolerably convex, inequilateral, whitish both within and without, 

 never poHshed but often shghtly glossed, covered with an ashy 

 epidermis, under which it is nearly smooth or merely marked with 

 the lines of growth ; ventral edge ascending beliind, moderately 

 convex ; anterior side the shorter, rounded at its extremity, its 

 dorsal edge convex and somewhat sloping, but near the acute and 

 prominent beaks slightly incurved ; hinder side obtusely wedge- 

 shaped, the hgamental edge nearly straight ; umbonal ridge tole- 

 rably evident ; the ventral sinus almost obsolete ; ligament large 

 and moderately projecting. 



Iceland and Greenland. 



182. Tellina nasuta (pi. Ixiv. f, 224.) Conrad, Jour. Ac. 

 Nat. Sc. Pliilad. vol. vii. p. 258 ; Hani. Des. Cat. p. 71. sup. 1. 14. 

 f.7. 



T. testa ovato-oblonga, sohda, iuEequilaterali, convexa, impolita, 

 sublsevigata, albida, epidermide cinerascente plerumque induta; 

 margine ventrali medio subretuso ; dorsali antice convexo paulu- 

 lumque declivi, postice elongato recto et declivi ; latere antico bre- 

 viore, rotundato ; postico cuneiformi ; cxtremitate postica subbi- 

 angulata ; natibus obtusis ; lunula nuUa ; flexura costaque um- 



