24 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 
ming-net is shaken out in a dish of water. The clams may then 
be separated from the myriads of other small organisms by gently 
tapping the dish, when they will stop swimming, close their shells, 
and fall to the bottom. They are then easily picked up with a 
pipette, and transferred in a drop of water to a watch crystal un- 
der the microscope. When first caught they vary considerably in 
size, some being four times the diameter of others, as shown in the 
figure (Fig. 1). As one watches these specimens under the micro- 
scope he will frequently see one of them open its shell, thrust out 
and expand a circular swimming-organ and go whirling about in 
the water for a while; then as suddenly, this organ, the velum, is 
drawn in, the shells close over it, and the clam falls to the bot- 
tom and remains quiet. Figure 4 is a free-hand sketch of one of 
these swimming clams (caught on May 29) with the swimming- 
organ expanded, Around the margin of the latter are the rapidly 
moving cilia, which create a current of water in the direction indi- 
sated by the arrows. This specimen had struck a snag, and was 
held by it while the sketch was made ; smaller organisms and par- 
ticles of dirt were swiftly swept backwards, meanwhile, by the en- 
ergetic strokes of the cilia. In the midst of the organ is a long, 
slowly moving flagellum or lash, which may, perhaps, serve as a 
feeler. 
Inasmuch as there are no published figures of the clam at this 
stage, it was not possible upon the mere examination of these 
creatures to say definitely that they were the young of the soft- 
shelled clam. It was presumed that they were, however, not only 
from their appearance but from the fact that the adult clams a week 
or two before were ready to lay, and, further, from the fact that by 
the last of June the young set of clams is well started. (See Kel- 
loge’s Report, 1898.) The absolute proof that they were clams was 
forthcoming, however, for a number of specimens were isolated 
and kept alive in dishes for several weeks. During the first week 
or two they grew considerably, lost their swimming-organ, and 
took on unmistakable characters of the soft-shelled clam. Figure 
2is from a camera drawing of one of these living clams two weeks 
