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Rh row, elongate chondrophore which is flanked on each side by a fluted tooth and a socket. Plicatula gibbosa Lamarck Kitten's Paw Plate 356 North CaroHna to Florida, the Gulf States and West Indies, About I inch in length, somewhat cat's-paw-shaped. Shell strong, heavy, with 5 to 7 high ribs which give the valves a wavy, interlocking margin. Hinge in upper valve with 2 strong, equally sized teeth; lower attached valve with 2 sockets in the hinge with 2 smaller teeth set rather close together. Color dirty-white to gray with red-brown or purplish lines on the ribs. A common intertidal to offshore species. Family PECTINIDAE Because of the great number of fossil and living species of scallops and the almost limitless modifications exhibited by them, there have been no less than 50 genera and subgenera proposed in this family by various authors. Doubtlessly, many more will be invented. Most, if not all, of these genera are closely integrated by connecting species. Workers have a choice of using the single genus, Pecteji, or employing a genus for nearly every species. We are arbitrarily employing only six genera — Pecte??, Aequipecten, Chla- 772ys, Placopecten, Lyropecteii and Himiites — and we cannot justify these on biological grounds. It may be noted that we have moved the glassy, thin- shelled Propeamiisshim from the Pectinidae into a family of its own on anatomical grounds. This new family refers to what was once called "Amus- siidae." True Aumsiwn, however, is merely a subgenus of Pecteii connected to it by a series of species in the Euvola group. Genus Pecten Miiller 1776 Subgenus Pecten s. str. Pecten diegensis Dall San Diego Scallop Plate 336 Cordell Bank, California, to Lower California. 2 to 3 inches in size. Right valve convex with 22 or 23 flat-topped ribs which are generally longitudinally ridged on top. Left valve much flatter, with 21 to 22 narrow, rounded ribs. Dredged from 10 to 75 fathoms. Subgenus Patinopecten Dall 1898 Pecten caurinus Gould Giant Pacific Scallop Plate 29b Wrangell, Alaska, to Humboldt Bay, California.