372 JULIA ELEANOR MOODY 



me to be fully extended soon after the animal settles down to 

 the bottom of the culture dish, and not shot out on the approach 

 of the prey. This conclusion is based upon many observations 

 of the living animal under the immersion lens, in which I have 

 seen no further elongation of the tentacles at the approach of 

 Halteria. When fully extended, the tentacles are turgid, the 

 ends packed with the dark granular trichocyst material. It 

 seems probable that the impact of the soft body of Halteria 

 against the denser protoplasm of the tentacle is sufficient to 

 drive the latter into the body of the small ciliate, the trichocyst 

 material, forced either thi-ough a minute pore or from the rup- 

 tured tip, paralyzing the prey. By contraction of the tentacle 

 the Halteria is gradually drawn close to the body of its captor 

 and worked into the mouth by the action of the cilia. 



It sometimes happens that the tentacles, stretched out to 

 a great length, become entirely detached from the body. The 

 individual represented in figures 3, 4, 5 and 6 was under obser- 

 vation in a hanging drop for one hour and fifteen minutes. At 

 the beginning of the time it was normal in appearance, swimming 

 actively about; at the end of fifteen minutes it came to rest, 

 mouth downward. Under ordinary conditions the tentacles 

 are extended gradually from the entire surface of the body, 

 but in this case, only three or four were extended, these differing 

 from the normal tentacle inasmuch as they were of enormous 

 length and sinuous in outline (fig. 43). At this stage Actino- 

 bolus began to rotate very slowly, the extended tentacles, all 

 of great length, increasing in number; then swimming slowly 

 forward, it left in its wake a long trail of cast-off" tentacles, 

 many of which showed a worm -like motion (fig. 44) . Whether 

 this motion was due to the independent action of the tentacles 

 or to a motion transferred from the cilia to the trailing cluster 

 of detached organs, I am not prepared to say. After swimming 

 about for half an hour, Actinobolus, having freed itself of the 

 tangle of liberated tentacles, came to rest. For some minutes 

 the ciliary action was very rapid, but this gradually became 

 slower and finally ceased. Within a few minutes a break ap- 

 peared on the periphery of the posterior end which was followed 



