306 TESTACEOUS MOLLUSCA. 



purple, armed with numerous radiating rather obtuse ribs. Inside 

 white, with a flaky border of the external colouring in the upper 

 valve : cardinal denticles distinct : edges simple. 2i. Chili. It 

 has the general aspect of Edulis. 



O. Webbii. Recluz, Journ. Conch, ii. p. 256, t. S,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 in front, encircled 

 with distant thin short obliquely inclined simple lamellae : beaks 

 truncated. If. W. Indies. The shape is of course variable, but is 

 never peaked, apparently, at the beaks. 



** Margin with distinct folds. 



O. Cucullata. Born, t. 6, f. 11, YZ.—Lam.M.—E. 1. 182,/. 1, 2. 

 —Fav. t. 45, /. E.— D. p. Wl.—Desh. in E. 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 in 

 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. Philipjnnes, &c.' 



1 I am unable to discover any permanent distinguishing characters 

 in the " O. Cornucopia. Lam. 33. — Fav. t. 45, E. — E. t. 181,/. 4, 

 5. — Ch. f. 679. — W. t. 11, /. 69. Ovate- wedge- shaped, rounded at 

 the apex, plicated beneath and at the margin : lower valve cucullate. 

 Larger than Cucullata, its 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. 1 possess a 

 group of young individuals armed with tubular spines, and hence 

 scarcely distinguishable from Stellata or Spinosa. Another extreme 

 variety from the Philippines demands a separate description. The 

 lower valve, which is not ill represented in Knorr (5, t. 14,/. 4), was 

 attached to dead shells at the apex solely : 



O Cucullata, var. Tebebratulifokmis. Small, solid, the upper 

 valve moderately convex, purplish grey, with crowded depressed con- 

 centric lamella) 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. 



