The Soft Clam 285 



on bottoms bearing clean objects for the attachment of 

 the young. Some of these same conditions are also re- 

 quired by Mya, but many are different. The more im- 

 portant ones that have been observed, may be men- 

 tioned briefly. 



Even on a flat that has not been greatly modified by 

 man, it will be seen that clams do not grow everywhere. 

 A little observation may reveal the reason, or reasons, for 

 the existence of these barren patches. Perhaps ripple 

 marks have been left here by the retreating tide. That 

 means that the surface sand is loose, and shifts easily 

 under the action of waves or currents. Now if clams 

 were planted on such a bottom, it would be found that 

 when sand grains, carried by the water, touched the 

 sensory tentacles at the end of the incurrent siphon open- 

 ing, the whole organ would be withdrawn for a greater 

 or less distance into the burrow. Into the pit thus left, 

 the sand gradually settles, and is densely packed. Ap- 

 parently clams are not able to push this sand out. It is 

 not so easy a task as that of pushing the siphons through 

 loose sand or mud piled up by the clam digger on the 

 surface of the ground, and the creatures are smothered. 



Therefore, if one is to become a clam culturist, one 

 of the first things he must do is to select a bottom for 

 his clam bed that has a tenacious soil. Even when he 

 has found a bottom that does not shift under ordinary 

 conditions, he should remember that great gales, that 

 may be expected from definite directions, may tear it up 

 if it is in a position to be exposed to them. The No- 

 vember gale of 1898, from which time is sometimes reck- 

 oned on the New England coast, made many remarkable 

 changes in clam flats all along the shore. Many beds 

 were overwhelmed with sand or smothered with eel-grass 



