38 



ROBERT RIKMENSPOEL 



50 100 



RADIUS OF ORBIT (|im) 



Fig. 7. Correlation between the asymmetry of the tail wave and the 

 curvature of the orbit of sperm swimming in circles. 



metry relative to the tangent of the circular orbit. This asymmetry, 

 expressed as (b 2 — b^/b (where b x is the amplitude toward the cen- 

 ter of curvature of the orbit, b 2 the opposite amplitude, and b the 

 average), shows some correlation to the curvature of the orbit, as 

 shown in Fig. 7. 



The mean amplitude b of the tail wave is again quadratically re- 

 lated to the velocity of the cell, 



v = S„ ir -6 2 



and for S cir is found, 



0.8 u" 1 sec" 1 



It is thus seen that the efficiency of the flat tail waves (represented by 

 8 cir ) is less than that of the helical waves (see above). 



The frequency of the tail wave can be measured for circularly 

 orbiting cells, since no rotation is interfering with the picture. No 

 correlation between this frequency and the velocity was observed. 



Discussion Concerning Cell Movement 



Of the two types of movement described, the rotating type is to be 

 considered normal, and the nonrotating one as pathologic. The main 



