lit 
Genus.—LITHODOMUS, Couvier, 
Subcylindrical, rounded at both ends; beaks nearly 
terminal ; no teeth ; ligamental line nearly straight. 
L. LirHopHacus. Lin. 1156.—Lin. T. 8. p. 270. 
t. 6. f. 1. to 5.—Cuticle green, finely striated by the 
layers of growth; inside glossy, iridescent. 0,40...1. 
Limestone, very rare. 
Grenus.—PINNA. 
Longitudinal, equivalve, cunieform, acute at the beaks, 
gaping at the opposite extremity ; beaks straight ; 
hinge lateral and toothless; ligament marginal, 
linear, very long, almost internal. 
P. Increns. Pen. 4. p. 115.—Mont. p. 180.—Lam. 
13.—Mont. p. 180.—F. p. 406.—P. Lavis. ¢. 152. 
—P. Increns. & Fraeiuis. Turt. B. p. 222. t. 22. fi 
].—Oval-triangular, semitransparent, horn coloured, 
with concentric arched strize, a few longitudinal obsolete 
ridges towards the back ; ligamental edge straight, com- 
pressed anteriorly, from whence it runs almost directly 
for two-thirds and then slopes suddenly to the beaks. 
6...12. 8. Coasts, deep water. 
P. Fraciurs. Pen. 4. p. 114. ¢. 69. f. 80.—F. p. 
406.—P. MuricatTa. Don. ¢.10.—PEcTINATA. Mont: 
p-178.—Turt. B. p. 223, t. 19. f. 1.—Triangular, 
