REPORT OF COMMISSIONERS OF INLAND FISHERIES. 35 



and has buried itself in the soil; by means of it the clam attaches 

 itself to grains of sand within its burrow and thus anchors itself. 



THE COMMENCEMENT OF BURROWING. 



Clams begin to burrow as soon as they find a favorable location. 

 This may be soon after they cease swimming, or, if they have a 

 chance to settle upon sea-weed or other objects not near the ground, 

 it may be weeks before the burrowing actually begins. Even after 

 they haA^e burrowed, they seem for a time to be restless, and, as 

 first observed by Kellogg, the small clams, even those sometimes 

 an inch and a half in length, will leave their burrows without appar- 

 ent reason and wander about. Kellogg saw one such specimen try 

 six different places in three days. Usually before they reach this 

 size, however, they are permanently located and evidently satis- 

 fied to pass their allotted years in one jjlace. The period of com- 

 mencement of burrowing is a critical one for many reasons. The 

 young clams cannot live far below the surface, and though they may 

 anchor themselves within their burrows, they are still liable to be 

 washed out by storms, crowded out by their neighbors if the set is 

 very thick, or dug out by crabs,, eels, duck, and other enemies. It 

 often happens, too, that localities which are particularly favorable 

 for setting are entirely unfit for subsequent growth. Specific in- 

 stances have not infrec[uently come to our notice in which abundant 

 sets have practically been exterminated b}' decajdng sea-weed or 

 shifting sand. 



GROWTH AND AGE AT SEXUAL MATURITY. 



Just how long the clam lives has not yet been determined, owning 

 to the diflfiiculty in finding rehable marks of age. The growth dur- 

 ing the first few years has been carefully traced in our experiments, 

 and it is evident that the growth becomes slower with advancing 

 age. Considering the very large size of clams frequently found in 

 flats which are exposed only at extremely low winter tides, to- 



