TESTACEOUS MOLLUSCA. 285 
or purple, with twenty-five angulated ribs whose sides are serrated, 
and angle armed with erect scales, no interstices. 31...34,. New 
Holland. 
P. Austrauis, Sow. Th. f. 210, 220. Suboval, ventricose, 
thickish, equivalve, inequilateral, anteriorly somewhat spread ; ears 
unequal, with scabrous sulci; the twenty-three thick subangulated 
ribs composed of two rows of small sharp points, and a central 
ridge with scales, the interstices flat. 13....1,9,. Swan River. 
P. Varius*. Pen. 4, p. 221, t. 64, f. 1.—Lam. 47.—Mont. p. 
146.—Turt.. B. p. 214. Sow. Th. f. 214, 218.—Osrrea, V. 
Lin. 1146.—D. p. 260.—W. t. 10, f. 31.—Don. t. 1, f. 1.—Ch. f. 
633, 4.—List. t. 180 and 181, f, 18, t. 189. f. 28.—(Da Cos. t. 10, 
f. 1,4, 5, 7.)—O. Muricata, Punctata, VERstcotor. (Sow. Th. 
f: 216.) Incarnata, Gmelin. Suboval, thin, not quite regular ; 
upper valve slightly the larger, the umbones narrow and ventricose ; 
ears very unequal, rough with muricated sulci, the anterior small 
and obtuse, the posterior large, acute, and in the upper valve con- 
siderably overlapping the other at the margin, with the sinus very 
large: extremely variable in colouring, (when mottled the white 
patches are usually angulated) the squarish and distant ribs are from 
twenty-seven to thirty, and muricated by distant erect sharp scales ; 
the interstices smooth, and rather larger than the ribs. 24... 2. 
Great Britain and Mediterranean. P. Pusio Lam. (not Tin.) I re- 
gard as a depauperated variety. 
P. Sprenpiputus. Sow. Th. f. 246. Subtriangular, thin, com- 
pressed, angulated at the sides, ears very unequal, with scaly sulci, 
flat, the posterior broad and elongated, the sinus large; red, banded 
at the sides and ears with elongated white spots, the twenty-five 
neat rather distant and rounded subquadrate ribs armed with distant 
erect and acute scales. 1,4)...14... Singapore. More compressed 
and regular than the last. 
P. Sanecuineus. Lam. 48.—Sow. Th. f. 221,2.—Ostrea, S. 
Tin. 1146.—D. p. 259, in part.—Ch. f. 628.—W. t. 10, f. 29. 
Oval, rather compressed, regular, equivalve, subequilateral; ears 
unequal, with muricated sulci, the margins elevated, the posterior 
elongated : the twenty-five thick subangulated ribs armed with nume- 
ous erect angulated small scales, and toothed at the margin, the 
interstices narrow and flat: blood red variegated with white or 
grey. Var. Mottled with black and white. 139...1+1,...Philippines. 
P. Mintaceus. Lam. 54.—Del. t. 16, f. 6.—Sow. Th. f. 247. 
Oval, compressed, subequivalve ; ears unequal, with minute scabrous 
sulci; red variegated by white undulating patches beneath which 
the ribs are doomed by minute concentric lines; the thirty rounded 
ribs minutely serrated at the sides and annulated by obliterated 
scales, the interstices flat. 1,),...14°5. 
