LEE BARKER WALTON 145 



a compensatory motion may have for the organism in 

 which it exists. No explanation has been suggested other 

 than this as to the origin of the rotation, and without 

 further thought it is evident that one would be inclined 

 to attribute it to natural selection, assuming that those 

 individuals in which it did not occur were at a disad- 

 vantage in the struggle for existence by reason of their 

 more confined movement. 



It is the phase of the question dealing with the particu- 

 lar causes bringing about the rotation that appears to be 

 of extreme significance when considered in connection 

 with the principles underlying evolution and to be sus- 

 ceptible to quite another explanation than the natural 

 selection implied by the term *'adaptiveness" which, in 

 accordance with Jennings (1906), is based on the idea 

 that "it tends to preserve the life of the animal." Fur- 

 thermore, when the groups of facts associated with the 

 characteristic rotation are brought in review, it would 

 seem that the explanation suggested may go far toward 

 interpreting the origin of the fundamental activities as 

 well as the origin of the characters in general of organisms. 



In connection with the preparation of a systematic re- 

 view of the order Euglenoidina belonging to the class 

 Flagellata of the Protozoa (1915), it was noted with de- 

 cided interest that a large number of the forms possessed an 

 oblique striation ranging from almost indiscernible mark- 

 ings to characters of great complexity impressed upon a 

 cellulose-like envelope (e. g., Euglena spirogyra Ehrenb., 

 Phacus pyrnin (Ehrenb.), Heteronema spirale Klebs, 

 etc.), the striae extending forward and to the left. The 

 character also appeared to be invariably correlated with 

 an axial rotation of the organism from right over to left. 

 Such a movement is to be described in physical terms as 

 "clockwise," the position of the observer being in front 

 of the advancing organism. 



The facts took on additional interest when it was noted 

 that forms with a reverse striation seemed entirely absent 

 from the northern hemisphere, although such forms ex- 

 isted in the southern hemisphere. 



Inasmuch as the euglenoids are in general positively 



