192°] Taylor: Nt womotor Apparatus in Euplotes 443 



upon careful observation. Nevertheless, the lack of coordinated move- 

 ment between the frontal and ventral and the anal cirri (these being 

 the animal's creeping feet), was not at all times conspicuous. In some 

 cases (four recorded instances), this coordination was apparently 

 about normal. Even here, however, it was obvious that the frontal cirri 

 sometimes initiated the movement which was then taken up by the anal 

 cirri, but this succession was not always evident; (2) the avoiding 

 reaction was very seldom observed. If the oral lip were touched by 

 the needle-point (a stimulus which normally induces the avoiding 

 reaction) the incised animal would infrequently give this reaction, but 

 more often would turn to the right anteriorly (cf. third creeping 

 movement, p. 428), thus avoiding the stimulus without performing the 

 preliminary backward movement (cf. second creeping movement, 

 p. 428). The three notable changes in swimming movements after the 

 incision were: (1) A tendency to swim in circuits to the right. This 

 reaction was particularly noticeable just after the incision was com- 

 pleted, when it became for a time the only swimming movement. The 

 tendency, nevertheless, persisted even until the w 7 ound was more or 

 less fully healed. (2) Sharp turns to the right were quite infrequent 

 and in a few eases were at no time observed (three of these were 

 recorded). This movement is effected chiefly by a strong, quick lash 

 of the outermost three or all five anal cirri. The performance of this 

 stroke is possible for these anal cirri after the fibers are cut, as will 

 later be shown, but apparently such strokes are not readily or simul- 

 taneously linked up with corresponding beats of the membranelles ; 

 (3) The backward swimming movement (number 6, p. 429) has not been 

 definitely observed, as yet, in any of these incised animals, even when 

 stimulated mechanically by means of the needle or chemically with 

 such reagents as methylene blue or acid solutions. In one instance, 

 this or a similar reaction was apparent, but of this I could not make 

 certain. It occurred upon adding a solution of methylene blue with a 

 needle pipette. The movement backward was only a short distance, 

 two or three times the animal's length; this was followed by rapid 

 circus movements to the right and was not repeated, as is usually the 

 case with a normal E. patella. 



Cutting the anal cirri fibers or the membranelle fiber or both near 

 the motorium, or destroying the motorium. — The general effects upon 

 swimming or creeping movements were definite, fairly constant, and 

 much the same after performing any of these incisions. These move- 

 ments have, in fact, already been described in the foregoing paragraph. 

 It is important, therefore, to note that the destruction of the motorium 



