TRIBE NYMl'HACEA. 79 



acute : interstices concave and transversely wrinkled ; one end de- 

 pressed ; margin entire, lunule minute. Africa. 



L Nuttalii. Conr. Jour. A.N.S. Phil. 7. p. 255 - '■ 20 - /• 

 2. Lenticular, broader than long, slightly compressed, cancellated, 

 the concentric lines very regular, lamelliform, prominent ; pos- 

 terior fold small and marginal ; the extremity emarginate above ; 

 ligamental edge little sloping, cardinal and lateral teeth distinct, 

 inner margin minutely crenulated. 1. — California. 



L. Childreni. Gray Ann. Phil. 25. — Z. J. I. p. 221. 

 — Sow. G.f. 2.— Reeve. t. 59./. 2.— Tellina C. W. S. t. \.f 1. 

 Sub-orbicular, longer than broad, inequivalve, white, nearly smooth, 

 sub-antiquated, very finely radiated, sub-striated. Length 3. — 

 Brazil. 



L. Rugifera. Reeve. Z. P. 1835. Rounded, lenticular, 

 rather convex, whitish, somewhat banded with reddish chesnut, the 

 radiating striae elevated and crossing the concentric ; lunule tri- 

 angular, impressed, minute : inside white. 2.. 2\. — New Holland. 

 — Not unlike Tigerina. 



DONAX. 



Transverse, equivalve, inequilateral; with the anterior side very 

 short and obtuse ; two 'primary teeth in one or both valves ; and 

 one or two lateral teeth, more or less distant ; ligament external, 

 sho7't, inserted at the posterior impression. 



Inner margin entire or nearly so. 



D. Scortum. Lin. 1126.— D. p. \4§.—Lam. \.—E. t. 

 260. f. 2.— Ch. f. 242, 5, 6, 7.—B. t. 4.f. 1, 2.—W. t. G.f. 1. 

 Triangular with the anterior slope acute and flattish, greyish 

 white, with usually a tinge of violet, and decussated elevated striae, 

 which become abruptly more distant towards the posterior end; 

 anterior depression somewhat heart-shaped and flat ; inside violet 

 towards the hinge, and the margin not quite entire : hinge with a 

 lateral tooth in each side. In old specimens the angular margin of 

 the anterior slope is armed with vaulted scales : in young (D. Pu- 

 bescens. Lin. 1127.— D. p. 149. — Ch.f. 2A.—E. t. 260./. 1. 

 — Lam. 2. — W. t. 6./. 2.) with serrated spines, li. . 2\. — India. 



D. Cuneata. Lin. U27.—D. p. 153.— Lam. 3.— Ch.f. 260. 

 —List. t. 392. / 231.— .B. vignette, p.52.—W. t. 6. /. 13. 

 Ovate, wedge-shaped, compressed posteriorly, anteriorly abruptly 

 truncated, convex and coarsely wrinkled transversely ; white or 

 pale grey, rayed with rufous drab or dark violet, and very minutely 

 striated longitudinally. — Variety. Rufous with white rays. — 

 Variety. (D. Granosa. Lam. 8.) with the rays livid violet, and 

 the angulated slope sub-granular. 1 . . \\. — Tranquebar. 



D. Compressa. Lam. 4. — E.vol. 2. p. 96. — List. t. 391./ 



