100 LIBBIE H. HYMAN 



that important problems may be attacked b}' means of this 

 relatively simple experimental method. 



Under Professor Child's direction, I have been carrying out 

 experiments along similar lines on several species of microdrilous 

 oligochaetes ; this paper is a partial report of the results of these 

 investigations. 



I. MATERIAL 



The following species have been used in these experiments: 

 Aeolosomatidae 



Aeolosoma hemprichii Ehrenberg. 

 Naididae 



Dero limosa Leidy. 



Dero furcata Oken. 



Stylaria lacustris Linnaeus. 



Chaetogaster diaphanus (iruithuisen. 



Nais elinguis Mtiller. 

 Lumbriculidae 



Lumbriculus inconstans Smith. 

 Tubificidae 



Tubifex tubifex Lamarck. 



Limnodrilus claparedianus Ratzel. 



Aeolosoma was obtained from ordinary Protozoan cultures 

 such as are made up for class use. The naids were collected 

 from old ponds and streams, especially Wolf Lake, Indiana, and 

 the Des Plaines River near Lyons, Illinois; quantities of mud and 

 vegetation were brought in from such places, and put into large 

 crystallizing dishes. I have not found it practicable to keep 

 any naids but Dero for any length of time in the laboratory, 

 but this form is readil}^ cultivated, and thrives and reproduces 

 rapidly if a small amount of fermenting grain is added to the 

 culture. The tubificids were collected in the same places and 

 in the same way as the naids ; they can be kept for months under 

 laboratory conditions, and are also benefited by the addition 

 of grain to the culture. Lumbriculus inconstans, unlike the 

 other fresh-water oligochaetes, is very restricted as to habitat, 

 occurring, in the Chicago vicinity at least, only in temporary 



