276 TRIBE PECTINIDES. 



nearly equal, substriated ; upper valve more ventricose, overlapping 

 the margin of the other, the five ribs broad and rounded ; lower 

 valve with four broad ribs which are almost in pairs ; colouring very 

 variable, being orange or purple, either uniform or mottled, 

 yellow variegated with grey and intermediate rays, and greyish 

 with zebra-like markings of brown. l r 7 y...l^f. Adriatic. 



P. Sulcatus. Lam. 21.— Sow. Th.f. 179^180. l.—Philippi. 1. 

 p. 79.— Ostrea S. Born, t, 6. f. 3.—D. p. 255. (partly).—?. 

 Flavidulus. Lam. — P. Solaris. Ch.f. 638. — Ostrea, S. W. t. 

 10, f. 40. Orbicular, rather flattened, with radiating striae; ears 

 nearly equal, broad and acutely angulated ; orange colour, blackish 

 brown or nearly white with brown spots ; with ten ribs which are 

 grooved, rounded elevated and equal. 1^. . ly . Mediterranean. 

 P. Unicolor. Sow. Th. f. 5, 6. — Lam. ? 23. — Reeve. Sys. t. 

 114. /. 5 ?—Regenf. t. 11. /. 50 1-~Knorr. I. t. 8. /. 5 ? 

 Rounded, rather irregular, inequivalve, rather ventricose, rather 

 smooth ; ears nearly equal and striated ; upper valve the more 

 ventricose and overlapping the margin of the other, its nine ribs 

 rather distant, rounded and somewhat depressed ; lower valve 

 rather flat, its ribs less elevated ; plain orange, or pale red with 

 concentric bands of light brown. 1^...1^q. Black Sea. 



P. Flexuosus. Lam. 38—Soiv. fh.f. 200 to 205.— Ostrea F. 

 Poll. 2.t. 28./. 1, 2,5, 11. — P. Polymorphic. Jay.— Philippi.p. 79? 

 — P. Isabella. Lam. 26. Subequilateral, rounded-fanshaped, 

 more or less ventricose, smooth or with obsolete radiating striae, 

 the margins usually inflected ; ears nearly equal, radiated, straight, 

 acutely angulated, emarginated at the base ; with five large gradu- 

 ally elevated ribs, sometimes with five small intermediate ones ; 

 variable in colouring : internal ribs in pairs, dentated at the margin. 

 -t*«*4> Mediterranean. 



P. Undulatus. Sow. Th. f. 206,7. Very like the last, but 

 the sides more spread, the margins angularly inflected, the ribs 

 more elevated : upper valve yellowish red, purple internally ; 

 under valve white, tinted with rose. 1^. . l^o* Mediterranean? 



P. Elevatus. Soiv. Th. /. 14, 15. — Ostrea Elevata. Poli. 

 t. 28./. 17. & O. Inflexa./. 4,5? P. Aspersus. Philippi.p. 81 ? 

 Rounded subtriangular, inequivalve, subequilateral, depressed, 

 most minutely cancellated, the umbones acuminated, the ventral 

 margin denticulated and usually inflexed ; ears small, the anterior 

 the less ; upper valve slightly hollowed in the centre, with five 

 large elevated gradually depressed ribs, which near the umbones 

 are angulated, near the margin inflated ; extremely pale rufous, 

 variegated with small red and radiating brown spots; lower valve 

 white, rather ventricose, with four large broad rounded and elevated 

 ribs . 1 J ... 1 -j l . Sicily . 



