No. 633] FREE-SWIMMING MASTIGOPHORA 



335 



existence. Adventitious individuals may bo derived 

 from such colonial mastigophora as Spouf/omonas, An- 

 \hoph\fsa, Dcndromonas, Urof/lcua, and Bumosonema. 



The following key, which was devised by the writer, 

 has been found helpful in the identification of the minute 

 forms, and in fixing in mind the characters that are the 

 most prominent, and that are useful, under the micro- 

 scope, in identification. The key includes practically all 

 the forms of the minute mastigophora that are likely to 

 be found in the waters of bogs, ponds, roadside ditches, 

 creeks, and brooks, and putrefying infusions, in so far as 

 these have been accorded systematic place. These 

 forms occur over and over again, and their identification 

 has been found to be a matter of loss difficulty than was 

 at first thought, before a definite plan for handling them 

 was formulated. 



