26 REPORT OF COMMISSIONERS OF INLAND FISHERIES, 
means of a curious kicking stroke of the very long foot. They 
were never taken in the tow except on this occasion, a rainy even- 
ing when a strong wind was blowing. 
Whatever method of swimming the young clams may finally use, 
it is certain that they swim freely in the water until the foot and 
siphon are developed and they are thus equipped for crawling 
about over the sea-weed, stones, sand, and other objects they 
happen to strike upon. 
A specimen whose swimming-days were past is represented in 
Fig. 5. The double nature of the siphon is shown at this stage, 
the incurrent and excurrent portions being almost separate from 
each other. The dotted lines represent the foot as it appears 
when the shell is closed, and the foot thrust out is represented by 
the solid lines. It is impossible to obtain more than a hasty 
camera sketch of the outstretched foot because its movement 1s So 
quick. The foot reaches out sometimes considerably further than 
the picture indicates, takes hold of the bottom of the dish, and 
with a quick jerk the shell is pulled up to it, the whole operation 
not occupying more than a second or two. By this rather clumsy 
method of travelling the clam is able to make considerable 
progress. 
A few days after the clams are caught at the surface they are 
found to have attached themselves to the bottom of the dish or to 
any object which happens to be near them. Kellogg found last 
year these very small specimens attached to sea-weeds and other 
objects and carefully studied their habits from this period of life, 
when they are less than one-fiftieth of an inch in length, until they 
are finally settled in the ground. He showed that they attach 
themselves to objects by spinning byssus threads as the mussels 
do, but that they can at pleasure release themselves from the at- 
tachments, crawl about and attach themselves again. The abil- 
ity to attach itself remains until the clam is upwards of one-half 
an inch in length, and by this time most of the clams which sur- 
vive have buried themselves in the ground. Fig. 24 is a lfe- 
size photograph of a small clump .of clams anchored by byssus 
