PLATE LXIY. 
1. Pecten Carinatus. (. Keeled Pecten.) Orbicular, elongated, convex; ears large, smooth, square ; surface, 
with about seventeen, longitudinal, rounded ribs, with a sharp keel on each, and broad, flat, intervening space, 
with sharp line along the middle. 
2. P. Nitidus. ( Shining Pecten.) Obovate, shining, one valve convex, with many, crenulated ridges ; other 
valve flat, with as many smooth ridges ; interstices striated transversely ; ears equal; margins entire. 
8. P. Jacobseus. ( Jacobean Pecten.) Upper valve flat, with about sixteen, longitudinally grooved, decus¬ 
sated, quadrangular ribs; lower valve with sixteen, grooved ribs and interstices transversely striated; ears 
equal, rectangular, with decussated striae. 
4, 5. P. Duplicatus. ( Double-plaited Pecten.) Orbicular, compressed; ears small, defined; surface, with one 
valve smooth, the other rough, with many, distant, rounded ribs, becoming from ten near the beak to about 
forty at basal margin; covered with minute, sharp scales. 
6. P. Orbicularis. ( Orbicular Pecten.) Orbicular, compressed; one valve smooth, with wide-set, sharp, 
concentric striae ; ears equal, large ; shell tender. 
7. P. Barbatus. ( Bearded Pecten.) Orbicular, compressed; ears nearly equal ; surface, with about fourteen, 
flattened ribs ; those on one valve with spines and transverse striae ; ribs on opposite valve convex, crossed by 
striae; sides of both valves pectinated near the ears. 
8. P. Cing'illatus. ( Banded Pecten.) Elongated ; ears small, equal; surface crossed by many, equidistant 
transverse ribs. 
9. 10. P. Millerii. ( Miller's Pecten.) Oblong-oval, inflated ; ears unequal, small; surface, with many 
smooth, divergent ribs. 
11. P. Similis. ( Similar Pecten.) Sub-orbicular, compressed; with longitudinal, arched striae ; ears unequal; 
sides nearly straight. 
12, 13, 14. P. Compositus. ( Composite Pecten.) Oblong, with about twenty, sharp, radiating ribs, and two 
rows of scales in each sulcus. 
15. P. Opercularis. (Lid-shaped'Pecten.) Orbicular; valves convex, with eighteen to twenty, tripartite 
ribs; surface, rough, with small scales; intercostal sulci, with longitudinal striae ; margins scolloped ; ears equal 
16. P. Dentatus. (Toothed Pecten.) Orbicular, convex ; ears small, unequal; surface, with about twenty, 
angular, longitudinal ribs, crossed by minute, concentric striae ; margin dentated. 
17. P. Maximus. (Great Pecten.) Upper valve flat, with fourteen to seventeen, longitudinally striated or 
grooved ribs; lower valve convex, with longitudinal striae; intercostal sulci of both valves striated; ears 
rectangular, with decussated striae. 
18. P. Striatus. (Striated Pecten.) Oval; valves equal, convex, with smooth, scaly ridges ; margins entire ; 
ears large, unequal; shell thick. 
19. P. Obliquus. (Oblique Pecten.) Obliquely oval; valves unequally convex; ears large; surface, with 
many ribs, roughened by imbricated scales, every third being larger than the other two. 
20. P. Vag’ans. (Wandering Pecten.) Ovate, convex; with about eleven, convex ribs, with large, concave 
scales ; ears equal, crossed by scales. 
21. P. Fibrosus. (Fibrous Pecten.) Orbicular, compressed ; ears equal, rectangular ; surface, with nine or 
ten, longitudinal, divergent sulci, and many, concentric striae ; beak rectangular ; margin internally undulated. 
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