1920] Taylor: Neuromotor Apparatus in Euplotes 447 



Another matter of considerable importance here concerns any 

 specific function which a group of organelles in E. patella may per- 

 form. Are there indications of a division of labor among the several 

 groups of cirri and membranelles? Since in many ciliates the body 

 is definitely differentiated and frequently bears several sorts of 

 organelles, such as cilia, cirri, membranelles, etc., some authors have 

 regarded this differentiation in the form and position of organelles 

 as representing a division of labor among the several groups. Pearl 

 (1900) concluded from observations on Colpidium that the effective 

 stroke of a group of anterior cilia, which is always toward the oral 

 side when the animal is stimulated by the electric current, caused the 

 body to turn toward the aboral side. Similarly, Putter (1900) observed 

 that the peristomial cilia in Stylonychia, with their effective stroke 

 toward the oral side, produced the swerving of the body toward the 

 aboral side. 



If these usual movements are effected wholly by a special group of 

 organelles, then the movements shoiild disappear upon the removal 

 of those structures. Accordingly, Jennings and Jamieson (1902) 

 undertook to ascertain the effect of the removal of one or more groups 

 of organelles in Stylonychia, Stentor, Spirostomum, and Paramoecium. 

 These investigators found that when any of these ciliates were cut into 

 pieces, "if they are not too minute or too irregular in form, the pieces 

 swim in a spiral, swerving continually toward a certain side, just as 

 do the entire organisms" (p. 232). It became evident, therefore, that 

 the usual reactions of these animals could not be attributed to any 

 particular set of structures, but that all the organelles have a share in 

 the production of these characteristic movements. 



The several transections made on E. patella, indicated a similar 

 tendency in the movements of each of the two pieces. Here, however, 

 tin' reactions were not so definite or so invariable as were those for 

 filiates described by Jennings and Jamieson (1902) . It will be recalled 

 that the swimming movements of E. patella are more varied than are 

 those described for the above animals. In addition to the spiral 

 swimming movement which is, indeed, very common in this ciliate, at 

 least five other characteristic swimming movements have been identi- 

 fied, three of which — the circus movement to the right, a sharp turn 

 to the right, and the backward, avoiding reaction — are by no means 

 uncommon. Furthermore, the transections have shown that the 

 anterior piece possessing only the group of three frontal cirri and 

 adoral membranelles swam almost constantly in circuits to the right. 



