TRIBE NYMPHACEA. 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. t. 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 creuulated. 1. — California. 



h. Childreni. Gray Ann. Phil. 25. — ^. J. 1. p. 221. 

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

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

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

 Brazil. 



L. RuGiFERA. Heeve. Z. P. 1835. Rounded, lenticular, 

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

 radiating strice 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, 

 short, inserted at the posterior impression. 



Inner margin entire or nearly so. 



D. ScoRTUM. Lin. 1126. — D. p. 148. — Lain. 1. — U. t. 

 260./. 2.— Ch. f. 242, 5, 6, 7.—B. t. 4./. 1, 2.— W. t. 6./. 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. H. . 2^. — India. 



D. CuNEATA. Lin. 1127.— B. p. l53.~Lam.3.—Ch.f. 260. 

 —List. t. 392./. 231.— i?. 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 Avith white rays. — 

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

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



D. CoMPREssA. Lain. A. — E. vol. 2. p. 96.— List. t. 391./. 



