THE BEHAVIOR OF PROTOZOA 79 
which many specimens gather at times. Of course they get 
no food in this way.” They make attempts on various other 
organisms with which they come into contact, but often 
fail on account of the toughness or large size of the organism 
attacked. 
What seems at first to be choice of prey is really some- 
thing quite different. The infusorian swallows what it 
can and not what it will. ‘The apparent choice of food,” 
says Mast, “is due to the fact that the seizing organ will 
adhere to some organisms and not to others. The Didinia 
come in contact with all sorts of objects in their random 
swimming and attempt to swallow all those to which the 
seizing organ will adhere.” After all Didinium like Para- 
mecium is a pretty simple sort of a creature in its be- 
havior. It has but a few simple tricks which it tries 
over and over again. Its going gunning with its armory 
of projectiles, its accurate sense of position and its marks- 
manship are all creations of the observer’s fancy. 
A protozoan exhibiting somewhat more complex behavior 
than is shown by Parameecium is the large ciliate Loxophyl- 
lum meleagris. This organism usually glides along the 
surface of objects by means of cilia on the side of the body, 
but at times it may swim in a spiral manner through the 
water. If strongly stimulated while swimming it may 
back off and turn in another direction much as Parameecium 
does, but the organism seems to be averse to swimming and 
generally takes advantage of the first opportunity to glide 
along over some solid object or the surface film. These 
gliding movements are carried on in a more or less rythmical 
way most of the time. The body is narrowed and elongated 
and swims forward for a short distance, then there is a con- 
traction resulting in making the body shorter and broader 
and at the same time a reversal of the effective beat of the 
