60 NATURE'S TEACHINGS. 



bearing," is given to it because it furnishes the British pearls 

 which were at one time so highly valued. 



Like other bivalve molluscs, this Unio has the two halves 

 of the shell fitting quite tightly upon each other, and, when 

 they are drawn together by the contraction of the internal 

 muscles, they can give a very severe pinch. In many un- 

 civilised parts of the world the natives take advantage of 

 this property, and use them as tweezers, chiefly for the pur- 

 pose of pulling out hairs which they are pleased to think are 

 not needed. 



I need not state that with all bivalves the power is increased 

 in proportion to the size of the shell. Even an Oyster can 

 pinch most severely, while the Giant Clam, the shell of which 

 weighs some four hundred pounds, could nearly take off a man's 

 leg if it seized him. 



Mr. J. Keast Lord, in his "Naturalist in British Colum- 

 bia," relates an amusing story that was told to him by an old 

 settler respecting the power of the Clam's grip : 



" You see, sir, as I was a-cruising down these flats about 

 sun-up, the tide jist at the nip, as it is now, I see a whole 

 pile of shoveller-ducks snabbling in the mud, and busy as dog- 

 fish in herring time. So I creeps down, and slap I let 'em 

 have it. Six on 'em turned over, and off went the pack, 

 gallows scared, and quacking like mad. 



"Down I runs to pick up the dead uns, when I see an 

 old mallard a-playing up all kinds o' antics, jumping, backing, 

 flapping, but fast by the head, as if he had his nose in a steel 

 irap ; and when I comes up to him, blest if a large Clam 

 hadn't hold of him, hard and fast, by the beak. 



" The old mallard might ha' tried his hardest, but may I never 

 bait a martin-trap again if that Clam wouldn't ha' held him agin 

 any odds till a tide run in, and then he'd ha' been a gone 

 shoveller sure as shooting. So I cracked up the Clam with 

 the butt of my old gun, and bagged the mallard." 



Of course the reader will remember that this was only an 

 ordinary Clam, and not one of the giant race. 



BELOW the shell are two very perfect instances of natural 

 Pincers, each acting in a different manner, but on the same 

 principle. 



