202 LORANDE LOSS WOODRUFF AND HOPE SPENCER 



it increasingly difficult to interpret Protozoan behavior in simple 

 terms. 



SUMMARY 



The essential points presented are: 



1. Spathidium does not possess trichocysts, and consequently 

 the extrusion of such structures is not responsible for the paralysis 

 of the prey. 



2. Trichites are present in the oral region, and form a paling 

 which is apparently comparable with the supporting rods about 

 the mouth in the more generalized gymnostomatous ciliates. 

 There is no conclusive evidence that the trichites are the locus 

 of the poison. 



3. Spathidium spathula, in our cultures, possesses clearly 

 defined micronuclei. Therefore, the Spathidium studied by 

 Moody must be interpreted as an amicronucleate race. 



4. The food of Spathidium is limited to small ciliates, but not 

 to members of the genus Colpidium. 



5. Spathidium comes in contact with its prey solely through 

 chance. 



6. Prey which has been paralyzed and has become removed 

 from the oral region of the Spathidium is recovered in a majority 

 of instances by a complex series of successively modified reactions, 

 indicating 'sensing at a distance.' 



7. The factor involved in the 'sensing at a distance' is ap- 

 parently a substance secreted by the Spathidium when the prey 

 is paralyzed. 



May 6. 1921. 



