TRIBE NYMPHACEA. 71 



hinge nearly central, with two small indistinct cardinal teeth in each 

 valve, and no lateral, f . . |. — W. Europe. 



T. BiMACULATA.* Liu. 1120.— JD. p. \0l.- Lam. 52.-~Ch. 

 f. 127.— iJ. t, 290. f. 9.— Don. t. 19. f. l.—Turt. B.p. 184.— 

 'Wood. G. C. t. 45./. 6.— TF. t. 4. f. 83, Triangularly rounded, 

 broad, smooth, whitish with two oblong crimson spots on the inside ; 

 lateral teeth in both valves. — Variety. Pale violet without the 

 spots, (C/t. /. 132. a.) — Var. Uniform orange.— Far. Orange 

 with interrupted linear purple rays. — Var. Pink with the two 

 spots. — Var. Uniform pink. Hinge with two lateral teeth in both 

 valves, f. — IF. Indies. 



T. Sexradiata.* Lam. 53.— T. V>im\cvla.t a. variety . D.p. 

 lOl.—E.t. 290. /. \0.—Ch.f. 132. h. Triangularly rounded 

 inequilateral, whitish, with six brownish blue somewhat interrupted 

 rays : darker within. — Variety. With violet arrowheaded spots 

 disposed inrays.— (r?<r^. B. t. S.f. 5.) ^ . . f.— TF. Indies. 



T. OsTHACEA. Lam. 54.— E. t. 290. /. 13. Roundish-ovate, 

 thin, flattened, whitish grey, with transverse striae, which are fine at 

 the beaks and coarse and ridge-like at the margin : anterior side 

 truncated, and with two folds. — Size of T. Tenuis. — India. 



T. Lata. Quoy. Ast. i. 81,/. 8, 9, 10, Ovate, broad, depressed, 

 inequilateral, posterior side the shorter angulated, transversely 

 striated ; white with elegant interrupted rays of red ; beaks acute 

 and purple ; margin with alternate white and red spots ; yellow 

 within. — South Seas. 



T. Nasuta. Con. Jour. A. N. S. Phil. 7. p. 258. Ovate, 

 compressed, smooth, dull, posteriorly dilated ; anterior side cunei- 

 form, extremity truncated, much above the line of the ventral edge : 

 fold carinated on the upper valve ; beaks central, slightly prominent; 

 epidermis brown, extremely thin and deciduous, finely wrinkled. 

 1} . . If. — Calif ornia. 



T. Edentula. Brod. and Sow. Z. J. 4. — Beechey Zool. t. 4\. 

 f5.md44.f. 7.—Lis.t. 40G.f.2o2.'f—An. Ch.f 74, T—E. t.290. 

 f. 3. ? Obovate, posteriorly longer, depressed, anteriorly shorter and 

 sub-angulated ; rather inequivalve, concentrically striated, whitish ; 

 ligament large : cardinal teeth obsolete, no lateral ones. 2 . . 2^. — 

 Behrinfs Straits. 



T. Alta, Conr. Journ. A. N. S. Phil. 7. p. 258. Sub-oval, 

 approaching to sub-orbicular, slightly ventricose, dull, roughish, 

 yellowish white, equilateral, with distinct prominent lines of growth, 

 posteriorly obtusely rounded ; deeper valve anteriorly biangulated, 

 the other with an angular groove ; margin broad direct slightly 

 emarginate at its extremity towards the base ; cardinal plate broad, 

 teeth long and prominent. — l|..lf. — California.— Outline not 

 unlike E. t. 231. f 1. 



T. Flexuosa, Say. Jour. A. N. S. Phil. 2, j). 303.-Subor- 



