smith: infusoria of Kansas. 149 



classification. The careful application of a solution of tannin 

 served to bring the animal almost to a standstill, while the 

 cilia moved vigorously. 



In classifying these forms, I have attempted to take into con- 

 sideration the great variation in size which such species are 

 liable to undergo. It is a well-known fact that different races 

 of Paramsecia vary to a marked degree in size, and it is also 

 well known that after one or two rapid divisions a protozoan is 

 reduced to one-half or one-fourth of its original bulk. It is 

 therefore, I believe, quite as absurd to attach too much im- 

 portance to size in classification of Protozoa as it would be to 

 declare a child not human because it is not so large as an adult. 

 That does not mean, however, that size is to be entirely neg- 

 lected, and as it is often convenient for the student to know 

 something of the variation in size of certain species I have in- 

 cluded, wherever expedient, not only the size of the specimen 

 at hand but also the range in size, or average size, of the 

 species, as indicated from a comparison of the work of various 

 writers. 



All drawings, with the exception of two plates of Heterotrichs 

 and a few fully extended forms or entire colonies, have been 

 made to the same scale, for convenience in rapid comparisons. 



A key has not been included in this report, because that was 

 deemed unnecessary until a more complete survey of the field 

 shall be made. The classification is, in general, that of Calkins. 



I have made no attempt to create new genera or species, be- 

 cause, unfortunately, I have been unable to collect all of the 

 literature upon the subject. I have, therefore, omitted for the 

 present most of the forms which I have been unable to classify. 



The species contained in this report have been taken from a 

 variety of sources, including: hay and leaf infusions, water 

 from ponds, surface pools, small creeks, watering troughs and 

 wells. 



In concluding this introduction, I take pleasure in acknowl- 

 edging my indebtedness to Miss Nadine Nowlin, under whose 

 direction the work was done, for the time and invaluable as- 

 sistance which was given whenever and wherever it was needed. 



