306 TESTACEOUS MOLLUSCA. 
purple, armed with numerous radiating rather obtuse ribs. Inside 
white, with a flaky border of the external colourmg in the upper 
valve: cardinal denticles distinct: edges simple. 23. Chili. It 
has the general aspect of Epuuts. 
O. Wessit. Récluz, Journ. Conch. ii. p. 256, t. 8, f. 1,2. Rounded- 
oval (often truncated on one side, and bluntly subangulated on the 
other), whitish; lower valve the larger, very deep, vaulted beneath 
the beak; upper valve flattened, a little convex m front, encircled 
with distant thin short obliquely inclined simple lamelle: beaks 
truncated. 12. W. Indies. The shape is of course variable, but is 
never peaked, apparently, at the beaks. 
O. Cucutuata. Born, t. 6, f. 11, 12.—Lam. 34.—E. t. 182, f. 1, 2. 
—Fav. t. 45, f. E—D. p. 277.—Desh. in EH. M. 2, p. 276. Very 
inequivalve, very solid, stained with purplish black on a white 
ground (wherever not eroded), with more or less obtusely angulated 
large radiating folds, that are often almost obsolete in the flattened 
and rounded upper valve, and are roughened by concentric scales m 
the lower valve, which is profound, and (in the adult) deeply excavated 
beneath the much produced beaks: inside white, not at all pearly: 
hinge-margin broad, the adjacent edges more or less denticulated, the 
more remote margin usually sprinkled with a few scattered granules. 
2. Philippines, &c.' 

1 T am unable to discover any permanent distinguishing characters 
in the “O. Cornucopia. Lam. 33.—FK av. t. 45, H.—EH. t. 181, f. 4, 
5.—Ch. f. 679.—W. t. 11, f. 69. | Ovate-wedge-shaped, rounded at 
the apex, plicated beneath and at the margin: lower valve cucullate. 
Larger than Cucuuiata, tts lower valve more expanded, and its edge 
not denticulated below.” 
It is almost impossible to define the limits of this widely extended 
species, which evidently varies according to its habitat. I possess a 
group of young individuals armed with tubular spines, and hence 
scarcely distinguishable from STeLLaTa or Sprnosa. Another extreme 
variety from the Philippines demands a separate description. The 
lower valve, which is not ill represented in Knorr (5, t. 14, f. 4), was 
attached to dead shells at the apex solely : 
O. CucuLuata, var. TEREBRATULIFORMIS. Small, solid, the upper 
valve moderately convex, purplish grey, with crowded depressed con- 
centric lamelle which indicate by their arrangement some obsolete 
radiating ribs: lower valve pale purple, the radiating ribs numerous, 
nearly smooth, rounded (not angular): cardinal denticles extending 
nearly around the entire margin: beaks inclined, 
