DESCRIPTION. 
135 
sides plaited, denticulate/ lower valve smooth, 
channelled in the middle, upper one rough with 
elevated points upon the margin, and an elevated 
central rib. 
Inhabits the American Ocean. 
Fig. 5. M. margaritiferus. 
Shell compressed, flat, suborbicular ; hinge 
transverse, imbricate, having the laminae toothed 
in rays. 
Lister Conch. Tab. 223. Fig. 57. 
Specimen whitish with crimson rays, within 
pearly ; being young, it does not possess the tooth- 
like scales which are found in older shells. Hinge 
very straight, the length of the whole shell. 
Inhabits the American Ocean. 
A distinct variety, differing in size and in other 
respects from the East Indian Pearl-bearing muscle. 
Fig. 6. M. edulis. 
Shell smooth, violet ; valves rather carinate 
before, retuse behind, beaks pointed. 
Lister sConch. Tab. 362. Fig. 200. 
