digging soon brought to light a whole spadeful of clams mixed with 

 mud, and we all gathered around to pick out some specimens for our 

 collections. They were the soft -shelled clams, having white shells 

 and remarkably long, black siphons. Upon close examination we found 

 that the siphon was not one tube, but two tubes joined together. Profes- 

 sor Parker told us that when the 

 clam is in its natural position it is 

 buried nearly a foot below the sur- 

 face of the mud, and its siphons 

 are stretched out until the end just 

 reaches a little above the surface. 

 In this position the lower siphon 

 is the larger, and is fringed with 

 little whip-like organs called cilia. 

 The other siphon is smaller, and is 

 without the larger cilia. When the 

 clam is disturbed, either by foot- 

 steps or by some enemy, it violently 

 retracts the siphons, thus causing 

 the water in its shell to shoot up in 

 a little spout. When the clam is 

 covered by the sea, all of the little 



cilia are engaged in pumping cur- 

 rents of water down one siphon and 

 up the other ; but when the tide is 

 out, the clam stops working and re- 

 mains quiet, with its siphons fully 

 extended. However, should an ene- 

 my alarm it, the siphons are sud- 

 denly drawn in. 



We spent the morning digging 

 clams, and by noon had accumulated nea-rly a bushel. Gathering together 

 a lot of seaweed, some driftwood, and a few large stones, we built a fire 

 in an inclosure formed by the stones, put on the seaweed, and soon 

 had a nice lot of clams baking for our dinner. 



While Harry was busy preparing the dinner, the rest of us walked 

 along the shore to pick up any good specimens which the tide might 

 have washed in. At the point which marked the height of the tide, 

 there was a line of debris called sea-wrack, which proved to be a per- 

 fect mine for specimens, and we gathered no less than twenty different 

 varieties of clams and snails. The Professor told us that such a locality 



62 



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A B 



Soft-shelled clams, Mya arenaria, buried 

 in the mud in natural positions. A, with 

 siphon extended; B, with siphon contracted. 



