1923] Kofoid-Swczy: Pentairkhomonas anlin delteili 383 



avoiding reaction of the ciliates. It can be observed most readily in 

 case of an individual temporarily anchored by the tip of the axostyle 

 or by the free flagelliim. 



A peculiar, rather regular wobbling characterizes the locomotion, 

 which appears to be due to a pendulation of the body about the axis 

 of progression which is correlated with the differential strokes of the 

 independent and clustered anterior fiagella. As a result, the two 

 ends describe approximately equal cones of rotation about the spiral 

 axis of progression. 



A persistent study of the location of the flagella in stained 

 preparations and during the slowing-down period in the margin of 

 the iodine-eosin stain in fresh smears has enabled us to distinguish the 

 differential strokes and to correlate them with the movement of the 

 undulating membrane and with the origin of the two groups from 

 the two blepharoplasts. 



The motion of the undulating membrane, as the slowing-down 

 process ensues, is resolved into a series of regular, successive beats 

 or contractions, which traverse the membrane as a series of character- 

 istic undulations. These do not, however, appear to run through the 

 free flagellum at the end. Each beat is synchronous with the stroke 

 of the independent anterior flagellum. This flagellum moves inde- 

 pendently of the other four, in a sweeping continuous stroke, starting 

 from the anterior position, across the right face of the body, assuming 

 that the cytostome defines the ventral side. This flagellum and the 

 undulating membrane arise from the same primary blepharoplast and 

 beat synchronously. 



The four remaining clustered anterior flagella all beat in a stroke 

 independently of the one just described. They appear to beat together 

 or in rapid and close succession so that in fixed material they are 

 often found in juxtaposition or closely spaced. They all arise from 

 the secondary blepharoplast. 



Not only are the strokes of the derivatives of the blepharoplasts 

 independent but they beat at different intervals. In one individual 

 in the early phases of slowing down, the strokes were carefully timed. 

 The undulations ran at the rate of 30 beats in 10 seconds. During 

 this time the body was rotating at the rate of 3.5 rotations in 10 

 seconds. In another instance the rate was 10 beats in 10 seconds. 

 The independent anterior flagellum beats in the same rhythm. The 

 four clustered flagella of this last individual were beating at the rate 

 of only 4 strokes in 10 seconds. No protoplasmic lobe was in evidence. 



