TRIBE NYMPHACEA. 71 
hinge nearly central, with two small indistinct cardinal teeth in each 
valve, and no lateral. §..3.—W. Europe. 
T. Brwacunata.* Lin. 1120.—D. p. 101.— Lam. 52.—Ch. 
J. 127.—£. t. 290. f. 9.—Don. t. 19. fi 1.—Turt. B. p. 184.— 
Wood. G. C. t. 45. f.6.—W. 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. (Ch. f. 132. a.)—Var. Uniform orange.—Var. Orange 
with interrupted linear purple rays.—Var. Pink with the two 
spots.— Var. Uniform pink. Hinge with two lateral teeth in both 
valves. 3.—W. Indies. 
T. Sexrapiata.* Lam. 53.—T. Bruacutata variety. D. p. 
101.—E. t. 290. f. 10.—Ch. f. 132. b. Triangularly rounded 
inequilateral, whitish, with six brownish blue somewhat interrupted 
rays: darker within.—Variety. With violet arrowheaded spots 
disposed in rays.—(Turt. B. t. 8. f.5.) 4..3.—W. Indies. | 
T. Osrracea. Lam. 54.--H. t. 290. f. 13. Roundish-ovate, 
thin, flattened, whitish grey, with transverse strize, 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. t. 81.f. 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. 
ie Nasura. Con. JourwAs Ns S. Phil. 7p. 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. 
13... 14.—California. 
T. Epenruta. Brod. and Sow. Z. J. 4.—Beechey Zool. t. 41. 
f.5.and44, f. 7.—Lis.t. 406. f.252.?—An. Ch. f. 74. ?—H. t. 290. 
J: 3.2 Obovate, posteriorly longer, depressed, anteriorly shorter and 
sub-angulated ; rather inequivalve, concentrically striated, whitish ; 
ligament large : cardinal teeth obsolete, no lateral ones. 2..23.— 
Behring’s Straits. 
T. Atra. 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.—1}..13.— California.— Outline not 
unlike E. t. 231. f. 1. 
T. Frexvosa, Say. Jour. A. N.S. Phil. 2. p. 303.—Subor- 
