Page:American Seashells (1954).djvu/444

362 6 to 8 inches in size, roughly circular; upper valve almost flat, reddish gray and with about 17 low, rounded ribs; lower valve deeper, whitish and with a few more, stronger, rather flat-topped ribs. This is the common, edible deep-sea scallop of Alaska. Subgenus Amusiujn Roding 1798 Pecten papyraceus Gabb Paper Scallop The Gulf of Mexico and the West Indies. About 2 inches in size, oily smooth, glossy, exterior without ribs, but internally with about 22 very fine ribs which are commonly arranged in pairs. Both valves moderately convex to flattish. Upper valve light-mauve to reddish brown with darker flecks. Lower valve whitish at the center with yellow to cream margins or all white. Hinge line strongly arched. Rather rare in collections, but commonly brought up from several fathoms by shrimp fishermen. Pecten laurenti Gmelin (pi. 33f) from the Greater Antilles is larger, with a straight hinge line and with the lighter-colored valve more convex than the darker valve. Rare. Section Euvola Dall 1897 Pecten ziczac Linne Zigzag Scallop Plate 33d North Carolina to Florida and the West Indies. 2 to 4 inches in size. Upper (left) valve flat; lower valve very deep and convex. There are 18 to 20 broad, very low, rather indistinct ribs on the deep valve which is generally colored a brownish red (rarely orange). The ribs fade out or are not present near the side margins of the valve. Flat valve with a bright mozaic of whites and browns. A fairly common species. Do not confuse with raveneli. Pecten raveneli Dall Ravenel's Scallop Plate 33g North Carolina, the Gulf of Mexico, and the West Indies. I to 2 inches in size, similar to ziczac, but the deep valve has about 25 very distinct ribs which are commonly whitish in color. Between them are fairly wide, tan or pinkish grooves. In the flat valve, the 25 or so ribs are rounded in cross-section whereas in ziczac they are flat-topped and much closer together. A rather uncommon species.