as a nucleus. Small images of Buddha were often used, doubtless strengthening 

 the faith of the superstitious pearl divers who later found the pearly images. 

 The Japanese later developed this process commercially. In this country 

 promising experiments in pearl culture have been carried out with the marine 

 abalone snail. Clams carrying pearls of any great size are often deformed, 

 the usual variation being a furrow down one valve and a corresponding eleva' 

 tion on the other. Sometimes the animal rids itself of the pearl, and the cast- 

 out pearl may be found among gravel. Because of the formation in concentric 

 layers a tarnished or discolored pearl can sometimes be restored to commercial 

 value by the removal of some of the outer layers, but this "peeling" is a task 

 for experts. 



Clams, like snails, should be gathered alive, if good shell specimens are 

 wanted. When the stream is muddy, it is usually possible to wade into shallow 

 water and feel around for them. If one is especially hardy, wading barefoot 

 is an excellent method of locating clams, but one must take care that he does 

 not get a practical demonstration of the reason why some clams are called 

 "■heel-splitters". A rake may occasionally be used to advantage. Commercial 

 clammcrs use a boat from which hangs a bar bearing several lines, each with 

 a twisted-wire, four-pronged, "crowfoot" hook. As the boat drifts slowly 

 downstream, the crowfoot bar is allowed to slide along the river bed. The 

 hooks enter the gaping posterior parts of the clams, which close tightly upon 

 them. After the boat has drifted for some distance, the bar is pulled up and 

 the clams that are found hanging to the hooks are removed. 



Having captured the clam, it may be opened either by dropping it into 

 hot water or by slipping a thin knife blade between the valves, on each side 

 of the hinge, and cutting the adductor muscles. The body of the animal can 

 then be removed and the shell washed. If it is overgrown with algae or en- 

 crusted with marl, a brief bath in oxalic acid will usually clean it. After the 

 shell is cleaned, it is advisable to give the epidermis a thin coat of vaseline 

 and to dry the shell slowly in a fairly cool place. Unless these precautions are 

 taken, the shell is likely to crack badly as it dries. The locality and date records 

 may be written with India ink or pencil on the lining of the shell. 

 Some Pointers For Identific.-\tion. 



If the soft parts of the clam are conspicuously colored, the collector should 

 make note of the fact, as it may aid in identification. For example, the animal 

 of iluadrida flava is orange-red, while that of ^uadrula coccmea, which 

 has a quite similar shell, is v^^hite. Strophitus undulatus, Decuramhis marginata 

 and Pleurohema cyphyum also have reddish soft parts, while most clams are 

 white or yellowish. The gills of the female clam may derive color from the 

 eggs carried in the ovisacs. Thus ^uadrula coccinea and ^uadrula undata 

 have red eggs, and the marsupium of each of these species therefore appears 

 to be red. 



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