The Fresh Water Pearl Makers 



Dr. N. M. Grier 

 Washington and Jefferson College, Washington, Pa. 



While most of the large group of animals known as the Mollusks 

 are capable of forming some sort of pearly secretion as a protection 

 against irritating objects, the group among them which becomes 

 more important each year in an economic sense is that of the pearly 

 fresh water mussels or Naiades. Known colloquially as clams, 

 they are familiar objects to many boys and girls who early learn to 

 trace them along the bottom of creeks and rivers by means of the 

 curious, winding and groove-like tracks portrayed in the illustra- 

 tion. Some kinds of them do not move about as much as others, 

 but all of them habitually lie embedded in the bottom, with the 

 hinder, (larger), end of the shell directed against the current and 

 slightly gaping, when they may be recognized if the water is suffi- 

 ciently low and clear, by the slit like appearance in the bottom. 

 Man has learned to take advantage of this peculiarity of the ani- 

 mals, for when it is desired to collect mussels for commercial pur- 

 poses, hooks are dragged on regions of the bottom where clams are 

 plentiful, and if such encounters the opening of the clam, the latter 

 closes its shell upon them, and even after a considerable interval 

 may be hauled up to the surface and pulled off. Depending upon 

 other conditions, various types of rakes and nets are also used for 

 securing the clams. 



Related more distantly to such animals as the pearly Nautilus, 

 the squids and octopus, and to the univalved snails — from which 

 latter type of animal evolution supposes they have proceeded, — 

 these bivalved animals are fundamentally similar in structure to 

 their relatives of the seacoasts — the oyster, hard and soft shelled 

 clams, scallops, edible mussels, etc. Gastronomically, they have 

 never received any equivalent appreciation and perhaps deserv- 

 ingly so, for while their meat is used for bait, or is sometimes fed to 

 poultry and pigs, human demand for it has never been great 

 enough to warrant the necessary separation of this aspect of their 

 utility from that of collecting them for shells and pearls alone. 

 Like all of their relatives however, the fresh water mussels are rich 

 in most necessary foodstuffs — protein and glycogen — facts un- 

 knowingly appreciated by those sections of the country using them 

 for food as the Indians are thought to have done. 



338 



