TRIBE OSTRACEA. 299 
O. Denticutata. Born, 113, t. 6, f. 9, 10 (copied E. t. 183, 
Ff. 3, 4)—O. D. var. b, Lam. 15. White, imequivalve, foliaceous ; 
upper valve the smaller, convex, subovate, glabrous ; lower valve flat 
(bemg attached by the entire surface), rounded, expanded : inner edge 
sharply toothed on both sides of the extremely broad and shining 
cartilage in one valve, with corresponding pits in the other; scar very 
large, somewhat reniform. 6. China? Judging from the figure, 
the attached valve, when permitted to develop itself, must, as in EDULIs, 
have distant foliaceous lamine, and not improbably radiating ribs ; 
the free valve has either lost its lamella, or they are much appressed ; 
2 or 3 marginal granules are, likewise, depicted. The O. DENTICULATA 
of Chemnitz (f. 672, 3, copied E. t. 183, f. 1, 2, and W.t. 11, f. 73), and 
of Deshayes (EL. 2, p. 289) are probably distinct. 
O. Sparuunata. Lam. 16.—Del. t.17, f. 1. Oval, longitudinal, 
dark brown or violet-black, moderately strong. Valves of equal 
length; the upper one shallow, covered with numerous concentric 
rows of loose but flattened lamelle ; the lower one moderately deep, 
with its lamella scarcely observable, but marked with obtuse radiating 
folds that undulate the margins. Inside white, edged in the upper 
valve with the dark hue of the external lamelle, and sometimes in 
the lower with dark blue: cartilage-plate rather large: cardinal den- 
ticles large, prominent and extending nearly (if not quite) over the 
entire periphery. 5. On mangrove branches, dc. 
O. Ruscurntana. Lam. 17. Oblong-ovate, thick (particularly the 
lower valve), bag-shaped under the beak: inside whitish, blackish 
purple at the margin: plate of the dorsal margin straight. “ Near 
Algiers; often pierced by Lithodomus caudigerus.” I do not know 
the species. 
O. Vireinica. Gmel. 3336.—Lam: 18.—D. p. 277.—Gould, Mas. 
p. 1387.— Last. t. 201, f. 34; t. 202, f. 35.— Fav. t. 41, f. C, 2.—E. 
-t. 179, f. 1 to 5.— Sow. G.—Reeve, Sys. t. 120, f. 2.—W. t. 11, f. 68. 
—D. p. 277. Elongated, narrow, nearly straight, very solid, not 
dilated and but little rounded at the base, sides more or less sub- 
parallel; valves rather shallow (the upper much depressed), dirty 
white, with concentric imbricated wrinkles (covered, when not worn, 
with crowded leaf-like scales of a dirty lead-colour): edges not waved, 
quite entire within ; beaks pointed, greatly produced in the adult, net 
curved. Inside white, with the scar subcentral and usually tinged 
with violet ; hinge as in the next species, with the successive removes 
of the cartilage indicated in the fossule by transverse wrinkles ; callus 
of the upper valve extending back to the apex. 12. Virginia; 
Mexico. 
O. Canapensts. Lam. 19.—K. M. t. 180, f. 1, 2, 3.—Ch. f. 677. 
—O. Borrauis, Gould, Mas. p. 137.— Young, O. BorEatis, Lam. 3,— 
