198 MANTON COPELAND 
it is in scme way directed toward it. From the experiments 
reported in the preceding pages, it is equally clear that the 
receptor particularly concerned with reactions to dilute chemical 
materials is unquestionably situated within the siphon, or its 
proximal continuation, the mantle cavity, a conclusion which 
was finally confirmed. With these facts in mind, the, problem 
of how the snail is directed toward distant food can now be 
approached. 
Attention has already been called to a conspicuous habit of 
Busycon associated with locomotion, that is: a lateral swing- 
ing of the siphon to the right and left. Not only the siphon, 
but the entire body above the upward neck-like extension 
of the foot, is involved in this movement. The foot proper is 
the only portion unaffected. The motion may be likened to the 
swinging of a compass needle before it comes to rest, the pivot, 
in the case of the snail, being the dorsal neck of the foot support- 
ing the shell and associated organs, the needle point being repre- 
sented by the siphon tip. 
It soon became evident that there was a mar ked difference in 
the direction taken by a moving animal dependent on whether 
stimulation by food juices occurred when the siphon was at the 
end of its swing to the right or to the left. When oyster extract 
was liberated in front of the siphon, when swung farthest to the 
right, the anterior end of the foot turned in the same direction 
and the animal, therefore, circled to the right. To ‘cause the 
snail to turn in the opposite direction, it was only necessary to 
apply the stimulating material when the siphon was swung to the 
left. When, however, the juice was squirted in front of the 
animal; that is, in a position so that the moving siphon end passed 
through it in the middle of its way from one side to the other, the 
snail tended to follow a straight course ahead. By appropriate 
stimulations, therefore, it was found that a snail could be actu- 
ally led about the aquarium in any direction, and even be made 
to leave the bottom and crawl up the side, provided the siphon 
first pointed in the direction which it was desired the animal 
should take. In. my notes are recorded over one hundred and 
forty cases where snails were directed from the bottom to one 
