TESTACEOUS MOLLUSGA. 281 
large, and in the lower valve very strongly emargimated ; ribs of 
the left valve from 9 to 13, thick, irregular, unequal, armed with 
coarse subquadrate scales, the interstices with irregular radiating 
sulci; of the right valve numerous and squamiferous. 23. Japan. 
P. Liviwus. Lam. 58.—Sow. Th. f. 61, 89, 91.—Ast. t. 76, 
f. 4, 5, 6.—Var. P. Sutepuurea. Lam. 57.—Ch. f. 629.  Irre- 
gular, suboval, subequivalve, compressed, foliaceous ; ears unequal, 
large, the posterior the larger and in the lower valve very strongly 
notched; with from 16 to 20 ribs which are unequal, scarcely 
raised, and armed with numerous acute scales, the interstices with 
irregular radiating sulci; variegated purplish brown, with the 
scales white or yellow. Variety. Scarcely mottled. Variety. 
Yellow. 23...24...Red Sea and Japan. 
P. Squamosus. Sow. Th. f. 48, 49, 50, 88, 92, 93.—Ostrea, S. 
Gmel.—Iist. t. 184, f. 21.—P. Hyprima (in part) Lam. 56. 
Variety B.—P. Araucisanus. Ch. f. 630, 1. Irregular, suboval, 
subequivalve, flat, foliaceous ; ears large, unequal, the posterior the 
larger, and in the lower valve very strongly notched; variable in 
coloring (often marked with fine ziezac lines of white, with from 
12to 18 almost obsolete, scaly ribs, which grow faint at the umbones, 
and in the lower valve are numerous and very slightly angulated. 
21-144... Northern Ocean. 
P. Serratus. Sow. Th. f. 56. Obliquely oval, irregular, an- 
teriorly somewhat produced, rather compressed ; the ears unequal, 
the anterior the smaller ; sulphur coloured, with large brown spots, 
the ribs numerous and most minutely scaly: inside purple at the 
margin. 12...14. Philippines. 
P. Irrecutaris. Sow. Th. f. 51, 2. Obliquely oval, subin- 
equivalve ; ears unequal, with scabrous sulci, the anterior small 
and obtuse, the posterior large and acute; scarlet with seven rays 
of interrupted white, mottled with purple; ribs numerous, small, 
scabrous, and subangulated. 1,9,...4 
P. Squamatus. Sow. Th. f. 57, 58.—Gmel. 3329.—Lis. t. 183, f 
20.—P. Rastettum. Reeve. Sys. t.114*, f. 3. Rounded, subtrian- 
gular,compressed, irregularly subequivalve, upper valve very slightly 
the more convex ; ears large and costated, with pointed scales, the 
posterior broad and somewhat acutely angulated; dull clouded 
brown, with, in one valve, from five to seven red broad rounded 
irregular ribs, which are armed with pointed scales, and fifteen 
smaller interstitial ones, the interstices most minutely punctated ; 
in the other valve the ribs are irregular, scaly, and unequal, 147 
eli. There is a white variety. i 
P. Brurr. Payr. p. 78, t. 2, f. 10,11.—Sow. Th. f. 241,2. 
Suborbicular, equivalve, subequilateral, yellow ; rays of the upper 
