126 



BIOLOGY OF THE PROTOZOA 



but may be found in some types of Gregarinida (see p. 535) and in 

 one group of the Radiolaria. The so-called myonemes of the 

 Trypanosomidae, however, are very doubtful kinetic elements but, 

 more probably, are analogous to the cuticular markings which are 



Fig. 70. — Epistylis plicatilis; longitudinal section showing myonemes (MY) from 

 membranelles to base of cell. (After Schroder.) 



frequently found on the periplast of flagellates. In some of the 

 gregarines, myonemes form a thick layer of extremely fine fibrils in 

 the cortex, running longitudinally and circularly, or possibly spirally, 

 about the cell, their contractions giving rise to the peristaltic move- 

 ment so characteristic of these forms (see p. 535.) 



