280 TRIBE PBCTINIDES. 



with black bands and white spots (also a purple variety) ; with 

 eight broad thick elevated and sulcated ribs, the interstices broader 

 and sulcated ; ears unequal, with nodose sulcations, the anterior 

 small, the posterior large. 2-J...2 T 9 ( y Mediterranean, fyc. 



P. Parvus. Soiv. Z. Ps 183$,-— 8m. Th. f. 227,8. Sub- 

 ovate, rather depressed, subequivalve, equilateral, whitish ; ears 

 unequal and granulated ; white with eight unequal transversely 

 striated radiating ribs, the interstices with radiating sulci and tran- 

 verse striae. -jf • • -4 Lord Hood's Island. 



P. Imbricatus. Lam. 31. — Reeve, t. 114*/. 2. — Sow. Th. f. 

 32,3.— Ostrea I. Gmel.33iS.-D. p. 252.— E. t. 214. /. 2.— 

 W.t. 10./. 12. {Worn shell. 0. Sauciata. Gmel.—Ch. £.69, 

 H. — W. t. 10./. 32.) Subtriangular, flat, nearly smooth, subequi- 

 valve ; ears unequal, flat, knobbed at the margin, the anterior small 

 and nodose, the posterior large and acute ; upper valve flat, with 

 nine rounded subangulated ribs, which are armed with hollow 

 imbricated tubercles, and alternately depressed : lower valve sub- 

 ventricose, the ten ribs noduliferous and equal. White spotted 

 with purple, the ribs alternately spotted with red ; inner disc yellow, 

 the margin purple. 1 J...l-j 3 <y Red Sea. 



P. Rubromaculatus. Sow. Th. f. 34. Oval subtriangular, 

 equivalve, subequilateral, somewhat compressed : ears unequal, 

 with scabrous sulci, the anterior small, the posterior large ; ribs 

 eighteen, scaly near the margin, alternately depressed and smaller, 

 the interstices slightly striated ; ribs of the lower valve numerous, 

 minutely squamular, unequal ; sulphur coloured, the more depressed 

 ribs with deep red spots in the centre of the shell. 1...0,92. 



P. Tigris. Lam. 30.— Sow. Th. f. 95,6.— Ch.f. 60S.— Phil. 

 Conch. Pecten, t. 1,/. 6. Subequivalve, obliquely subtriangular, 

 somewhat flat, rather scabrous, with strong internal ribs ; ears un- 

 equal, sulcated, the anterior small, the posterior acutely angulated ; 

 yellowish white with tiger-like stripes of dark reddish brown, and 

 eleven strongly grooved radiating ribs which are angulated above, 

 (the lateral ones small) the interstices grooved ; within yellow, 

 with a black band on the hinge and a pink spot at the base of the 

 posterior auricle of the upper valve, lj>«rj-* Philippines. 



P. Madreporarum. Petit. — Sow. Th.f. 68. Phil. Conch. Pecten, 

 t. 2,/. 4, 5. Obliquely ovate, compressed, irregular, with radiating 

 striae ; ears unequal, the posterior large, the anterior small ; white 

 with black spots and seven obsolete distant ribs. 4.. % Red Sea. 



P. Tegula. Sow. Th. f. 90.— Ostrea T. JV. S. t. 2. /. 3. 

 Subquadrate, irregular, subequivalve, compressed, foliaceous ; 

 brown very slightly variegated ; ears unequal, the posterior very 



* The P, Sauciatus of Lam. is probably a variety of Ornatus, 



