AVTHOR'S ABSTRACT OF THIS PAPER ISSfEP 

 BY THE BlBLIOOnAPinr SERVTCE, JILT 24 



THE PROCESS OF INGESTION IN THE CILIATE, 

 FRONTONIA^ 



WILLIAM M. GOLDSMITH 



Southwestern College, Winfield, Kansas 



TWENTY-FIVE FIGURES (THREE PLATES) 



INTRODUCTION 



The present paper is primarily a record of a series of observa- 

 tions on the ingestion of various kinds of food by the cihate, 

 Frontonia leucas, and on the relation which this unusual method 

 of ingestion bears to the variation in shape and habits of the 

 organism. The points of chief importance and interest in con- 

 nection with the present problem are as follows : 



1. Frontonia frequently takes food consisting of filaments 

 many times longer than itself. The manner of ingestion of 

 such food is explained in detail. 



2. The food of frontonia, is primarily diatoms, desmids, 

 euglenas, filaments of oscillatoria, and various other microscopic 

 plants. Various indigestible particles may also be ingested. 



3. The mouth of frontonia is normally very small as compared 

 with that of Paramecium and other common ciliates. How- 

 ever, it may be expanded to approximately two-thirds the length 

 of the body without injuring the organism. 



4. The normal shape of the body may be altered by certain 

 characteristic contractions, by simple twisting and bending, 

 and particularly by the presence of ingested materials. 



^ These investigations were carried on in the Zoological Laboratory of the 

 Johns Hopkins University during the year 1919-20, in connection with the regular 

 laboratory course in animal behavior. The writer is indebted to Prof. S. O. Mast 

 for many valuable suggestions during the progress of the work. He is also under 

 obligation to Prof. Asa A. Schaeffer, of the University of Tennessee, for reading 

 the manuscript. 



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