INLAND FISHERIES. 85 



the low tide mark. They are to be found here burrowed into the 

 sand, or attached to the sides of stones, down close to the line 

 where the stone touches the mud. This occurs most often on 

 stones covered by rockAveed {Fucud), and probably for the reason 

 that here the little clams find better protection from their most 

 destructive enemies, the young* starfish. It is possible that some 

 of these small clams between the tide marks originally attached 

 themselves in this position, never having been fastened to objects 

 in the Avater below low tide mark. 



This wholesale destruction of individuals below low water mark 

 is but another example of the tremendous strug-gle for life to which 

 so many species of organisms are subjected in nature. Of the 

 millions of swimming larva> that probably arise from one female 

 during" a breeding season, few become attached to suitable objects, 

 the water currents carrj^ing most of them away. Those which 

 succeed in fastening themselves are killed in vast numbers by very 

 small starfish ; and even after attaining a position in the sand and 

 mud of a favorable locality, the shifting of the sand, the crowding- 

 of individuals, the decay of organic material in the water, or the 

 isolation of salt water in shallow arms of the sea, leads to the de- 

 struction of many. Considering these phases of the life-history 

 of the soft clam which I have thus far descril:)ed, it seems that 

 artificial methods might be developed which should remove some 

 of the daniiers to be found in nature, and hence lead to a greater 

 increase in the number of adults. 



BURROWING INTO THE MUD. 



The migration from the point of attachment having been ac- 

 complished, we are next concerned with the habit of burrowing 

 into the mud. In the adult clam the foot is reduced to a laterally 

 compressed, finlike projection from the anterior side of the visceral 

 mass, not extending down on to its ventral surface. It is with 

 great difiiculty that the mature clam buries itself in the sand 

 after having been dug from its burrow. Clams from one to two 



