288 TRIBE PECTINIDES. 
PLICATULA 
Inequivalve, not auriculated, contracted towards the beaks, the 
ventral margin rounded and more or less folded ; beaks unequal and 
devoid of external ligamental areas. Hinge provided with two strong 
teeth in each valve which enclose the ligament between them. 
P. Ramosa. Lam. 1.—Desh. Enc. Met. 3, p. 801.—Crouch 
Int. t. 12, f. 5.—Spronvytus Pricatus (in part), Dil. 210.—Ch. 
f. 479,0.—Mawe Conc. t. 11, f. 2.—Oblong triangular, very 
thick, white with ferruginous longitudinal lineoles ; folds large and 
forked: hinge usually reddish, teeth striated. 14. America. 
P. Depressa. Lam. 2.—Desh. Enc. Meth. 3, p. 801. Oblong 
oval or subtriangular, usually more or less depressed, white with 
numerous small irregular brown spots which are chiefly upon the 
folds, which latter are numerous small and usually only apparent 
towards the margins; hinge dark brown; interior often stained 
with the same colour especially upon the scars. 14. America ? 
Lamarck refers with doubt to Gualt. 104, F. which is probably an 
Ostrea. 
P. Cristata. Lam, 3.—List. t. 210, fi 44.—Ch. f. 481, b— 
Blain. t. 62, f. 2.—Henderson’s Cuvier, t. 31, bis. f. 9. Oblong 
wedge-shaped, whitish or ferruginous, adorned with chocolate 
brown interrupted lines which are chiefly present upon the folds ; 
these latter are large, deep, simple, angulated and few in number, 
with frequently the appearance of being crested by the scales which 
in perfect specimens surmount their angles in one or both the 
valves. Var. Quite white. 1. America; W. Indies? 
P. Rentrormis. Lam. 4.—Sloan Jamaic. Histor. t. 241, f. 20, 21. 
Rounded, subarcuated, white, the folds simple, obtuse, squamiferous, 
and diverging. 1 Jamaica. The Type in the French Museum is 
rather depressed and has but seven or eight folds. 
P. Austratis. Lam. 6. More or less rounded or ovate, 
rarely if ever triangular, generally depressed and almost always 
attached by the whole of the lower valve; whi ish or ferruginous 
with numerous dark dots or small spots ; surfacenot folded but with 
very numerous close set squamular radiating riblets, which render 
the margin slightly wavy but not plicate@: inside uniform white. 
Var. Quite white. 14. Philippines and Australia. 
P. Impricata. Menke Moll. Nov. Holl. p. 35.—Rounded 
wedge-shaped rather depressed, strong, varying from smoky brown 
to bright orange, with numerous moderately subangular folds, some 
of which (in the very large specimens only) are usually forked near 
their termination, and all more or less armed with large vaulted 
seales. 15. 11. China; (deep nater, sandy mud) W. Australia. 
Tam indebted tothe courtesy of the author, for an examination of histype. 
