Tni/li'i-: Newromotor Apparatus in l-'.ni>l<>ttx 44it 



None \vtmM question tlic evidence for a division of lalior among the 

 intracytoplasmie organelles in tins ciliate. and the several experiments 

 previously deserilied would indicate that the extraeytoplasmir organ- 

 elles. also, may share a decree of speeilie. but none the less coordinated, 

 functions in the animal's normal behavior. Accordingly, in accom- 

 plishing such swimming nioveinents as the sharp turn to the right or 

 the (|iiick backward, avoiding reaction, we may regard the anal cirri 

 as especially etl'ective if not normally indispensable, much as the large 

 caudal cirri in I'rcnii/cliin- arc largely responsible for that animal's 

 very rapid, backward movements (Calkins. 11)11. p. l 1 ^ 



In this consideration, it is important to note that the feature of 

 coordinated activity is in all respects evident in the normal K. /xitilln. 

 The claim here made is that the perfection of both creeping and swim- 

 ming movements is dependent upon the cooperation particularly of 

 those organdies (e.g.. the frontal and anal cirri in creeping) which 

 contribute most effectively to the performance of any usual movement. 

 Therefore, the elimination of any important group of organelles, or 

 the interference with any mechanism by which they operate or 

 cooperate with another similarly important group, should result in 

 perceptible changes in swimming or in creeping movements. 



We may now enquire: Does the fibrillar system in Eui>1otes patella 

 re]) resent a mechanism that affects the external organelles individually? 

 Or does this complex, unified apparatus function in the coordination 

 of all the several groups of organelles with which it is intimately 

 associated? An affirmative reply to the first question would assign 

 either a supporting or a contractile function to this system, and to 

 affirm the second question is to attribute to the system the function of 

 conductivity. 



The experimental evidences set forth in previous paragraphs sup- 

 port an affirmative answer to the second question, viz., that this fibrillar 

 apparatus exhibits features of conductivity functioning to coordinate 

 the groups of external organelles with which its unified and dissociated 

 parts are directly or indirectly intimately associated. These evidences, 

 furthermore, do not support the assumption that the system is either 

 contractile or supporting in function. 



The facts which concern these three propositions may be stated as 

 follows : 



Tin fibrillar system in E. patella is not skeletal or supporting in 

 function. The rigid, fairly tough pellicle is amply sufficient to main- 

 tain the normal shape of the body under considerable stress. It was 



