310 TESTACEOUS MOLLUSCA. 
disposed throughout in numerous and regular rounded folds. Valves 
very unequal in convexity, but equal in length; the lower one pro- 
found; the upper one depressed, and divided into flattened ribs by a 
few broad grooves, its entire surface covered with numerous appressed 
imbricated lamellee. Inside whitish, the elongated denticles extending 
nearly or quite round the margin of the upper valve: scar oboval or 
suborbicular, rather large. 2. Philippines. In all the examples 
I have seen, the hinder side of the lower valve was the more elevated. 
O. Pyxtpara. Adams, Samar. p. 72, t. 21, f.19.  Orbicular, in- 
equivalve, dirty brown; both valves with radiating nodulous ribs, 
which in the extremely convex lower one are oftentimes double ; upper 
valve flat: ventral edge crenulated. 1. Philippines.) 
VULSELLA. 
Longitudinal, subequivalve, unattached, usually imbedded in sponge, 
pearly within; beaks of equal length. A rather prominent hinge- 
callosity, in each valve, flattened above and stamped with an obliquely 
arcuated conte cartilage-pit. 
V. Lineutata. (Kn. 5, t. 2, f. 1 to 3.)—Mya V., Lin. 1113.— 
Ch. f. 11.—D. p. 56.—V. L., Lam. 1.—E. t. 178, f. 4— Sow. G.— 
Reeve, C. S. t. 108.— Osrrea V., W.t.11, f. 84. Large, elongated 
1 Compare with the above the O. Morpax, Discorpna, GLOMERATA 
and Circumsuta of Gould (Proc. Bost. ii.), the O. Spreta .of 
D’Orbigny (Cuba), and the O. Curtiensis of Philippi (Aust. ed. Ch. vu. 
Tee 13): 
See, en O. GicantEa of Thunberg (Suecie Nov. Act. 1793), 
a coarse elongated oyster with depressed lamelle from Japan ; 
O. Forsxauu (Ch. 8, p. 30, f. 671, copied W. t. 11, f. 66), quoted by 
Philippi, and probably aright, for O. Cornucopia, O. CorBicuLus 
(Ch. 8, p. 44, f. 680.—O. Orsrcutaris, Dil. 278, not of Linneus, 
whose species was inadequately defined—IW. t. 11, fi 70); and 
O. Capsa of Fischer (Mus. Demid.) from Le Garin of Adanson 
(Sen. t. 14, f. 2). 
O. DentirerRA, Crocea and Exurerica of Dufo (An. Se. Nat. 
ser. 2) cannot be recognised by their descriptions. O. PApyRACEA 
of Gmelin (3337) and O. Paucrpiicara of Deshayes (Morée) are 
evidently immature; O. SemicyLinprica of Say (Jour. Ac. N.S, 
Philad.), an accident of growth. The O. Ovauis of Gmelin is 
solely taken from Schroter’s ‘ Einleitungen,’ vol. in. p. 378, t. 9, 
sh 
