THE WONDERS OF THE SHORE. 67 



drinking in the salt water tlirougli one of its 

 siphons, and discharging it again through the other. 

 Put the shell into a rock pool, or a basin of water, 

 and you will see the siphons clearly. The valves 

 gape apart some three quarters of an inch. The 

 semi-pellucid orange " mantle " fills the intermediate 

 space. Through that mantle, at the end from 

 which the foot curves, the siphons protrude ; two 

 thick short tubes joined side by side, their lips 

 fringed with pearly cirri, or tentacles, and very 

 beautiful they are. The larger is always open, 

 taking in the water, which is at once the animal's 

 food and air, and which, flowing over the delicate 

 inner surface of the mantle, at once oxygenates its 

 blood, and fills its stomach wi.th minute particles 

 of decayed organized matter. The smaller is shut. 

 Wait a minute, and it will open suddenly and 

 discharge a jet of clear water, which has been 

 robbed, I suppose, of its oxygen and its organic 

 matter. But, I suppose, your eyes will be rather 

 attracted by that same scarlet and orange foot, 

 which is being drawn in and thrust out to a length 

 f2 



