SOME USES OF CLAMS. 35 



meaning that which brings to. In the figure on page 

 31, the places of both the adductor muscles of the 

 clam are indicated (am). 



It is easy to see why, when a clam is opened with 

 a knife, the knife must be passed along the valve near 

 the front and back ; this is to cut the two adductor 

 muscles. Even with one of these muscles the clam 

 will close its shell, as an omnibus driver shuts the door 

 of his carriage by his foot-strap. 



A brother of the long clam is the round clam, some- 

 times called hard-shell, or little-neck-clam. Its awk- 

 ward foot is pushing out below and in front. It does 

 not dig, but hitches along by means of this foot. Its 

 short neck, or siphons, stretch out behind and above, 

 one with a fringe of hairs to paddle the water in, and 

 the other with the same kind of hairs to paddle the 

 water out. 



7. SOME USES OF CLAMS. 



THE largest of all shell animals is the giant-clam. 

 It is produced in tropical seas, and particularly in the 

 region of Sumatra. The famous Swedish naturalist 



o 



Linnaeus, who lived more than a hundred years ago, 

 describes one of these clams which weighed four hun- 

 dred and ninety-eight pounds. The mollusk within the 

 shell furnished a day's food for one hundred and 

 twenty men. So great was the strength of its muscle, 

 that by suddenly closing its valves it cut the cable of 

 a ship in two. 



