DERIVED ORGANIZATION— TAXONOMIC STRUCTURES 143 



swimming. When two flagella are present a curious shaking move- 

 ment may accompany rotation and translation. 



With such energetic motile organs exerting a constant strain on 

 the body there would seem to be some danger of their being pulled 

 out, especially in those types with soft fluid bodies without firm 



Fig 76.— Free-living flagellates with trailing flagella. A, C, D, Bodo caudatus St. 

 B, Bodo globosus St.; E, Ploeotia vitrea Duj. (After Calkins.) 



