TESTACEOUS MOLLUSCA. 979 



oblquely plicated ; ribs ten, thick, broad, with parallel nodo~ 

 sities, internally with tooth-like plaits. 2^...!-^. A smaller 

 shell than Nodosus, tvith the ribs equal and the knobs less con- 

 siderable. 



P. Magnificus. Sow. Zool. Pr. 1835.— Sow. 77/./. 114. Sub- 

 equi valve, equilateral, bright red, auricles unequal, with small very 

 crowded radiating striae, and thirteen radiating ribs which are thick- 

 ish rounded sometimes subnodose ; inside white with a purple 

 margin. 5§...5^. E. Columbia. 



P. Subnodosus. SowZ. P. 1835.— Sow. Th.f. 97, 112. Sub- 

 equivalve, equilateral, the ears unequal, with very crowded radiating 

 striae, and ten thick rounded radiating ribs, which are alternately 

 subnodulous, or armed with bladder-like knobs ; inside usually 

 stained with purple. 5J...5. Calif ornian, Var. Brownish red 

 with white striae. Columbian Var. Variegated with brown and 

 white patches. Mexican Var. Bright orange, more depressed. 

 Probably a variety of Nodosus. 



P. Nodosus. Lam. 27-— Sow. Th.f. 115 and 147.-— Ostrea. 

 N. Lin. 1145.— D. p. 254.— TV. t. 10/. n.—Rump.t. 48./. 8. 

 — P. CoRallinus. Ch.f 609. — Arg. t. 27, F. Orbicular, ventri- 

 cose, reddish brown or bright orange, subequilateral, equivalve, 

 with radiating sulci ; ears unequal, sulcated, the posterior the larger, 

 emarginated at the base ; hinge plicated ; the nine thick ribs armed 

 with hollow round knobs, alternately smaller, internally in pairs, 

 toothed at the margin. 5-J-...5. Brazil and Isle of France. 



P. Muscosus. Wood Sup. t. 2.f. 2. Subquadrate, extremely 

 ventricose, equilateral, equivalve, reddish brown, scabrous ; ears 

 unequal, elongated-acute, with scabrous sulci, notched at the base, 

 the posterior the longer : umbones prominent ; the eighteen sca- 

 brous and subangulated ribs armed with short straight spines at the 

 angle, and toothed at the margin, l^.,.!^ 



P. Rugosus. Sow. Jun. Z. P. Isi'Z.—Sow. Th. f. 226. Oval, 

 ventricose, thick, scabrous, equivalve, subequilateral, pale yellow- 

 ish, obscurely mottled with smoky brown, with twenty elevated ribs 

 armed with numerous small annulated scales, their edges serrated, 

 and their interstices smooth : ears unequal, with scabrous sulci, 

 the anterior the smaller, the posterior notched at the base. \\ 

 ...\\. Philippines. 



P. Pes Felis. Lam. 29.— Sow. Th.f 162 and ZU.— Reeve, t. 

 lU.fi.—Philippi. p. 84. Ostrea ' P. Gmel. 3323.— TV. t. 

 10./. 19.— D. p. 255,— Ch.f. 612,3.-0. Bornii. Pay. p. 76.— 

 0. Elongata. Born. t. 6./. 2. ?— O. Corallina, Poll 2. t. 28. 

 /. 16. Oval subtriangular, compressed, scabrous with radiating 

 sulci, equivalve, subequilateral, thick, reddish brown variegated 



