56 



PROTOZOOLOGY 



ectoplasm of the operculum (opercular fibers). A similar apparatus 

 has since been observed in many other ciliates: Euplotes CYocom; 

 Taylor), Balantiduum (McDonald), Paramecium (Rees; Brown; 

 Lund), Tintinnopsis (Campbell), Boveria (Pickard), Dileptus 

 (Visscher), Chlamydodon (MacDougall), Entorhipidium and Le- 

 chriopyla (Lynch), Eupoterion (MacLennan and Connell), Metopus 

 (Lucas), Troglodytella (Robertson), Oxytricha (Lund), Ancistruma 

 and Conchophthirus (Kidder), etc. 



Fig. 17. Diagrams showing the neuromotor apparatus of Euplotes pa- 

 tella (Taylor), a, diagrammatic dorsal view of the entire apparatus, 

 X1600; b, dissected portion of disintegrating membranella fiber plates 

 attached to the membranella fiber; c, a dissociated fiber plate of a frontal 

 cirrus with its attached fibers, X1450. acf, anal cirrus fiber; afp, anal fiber 

 plate; eg, small and large ectoplasmic granules; m, motorium; mf, mem- 

 branella fiber; mfp, membranella fiber plate. 



Euplotes patella, a common free-living hypotrichous ciliate, has 

 been known for nearly 50 years to possess definite fibrils connecting 

 the anal cirri with the anterior part of the body. Engelmann sug- 

 gested that their function was more or less nervelike, while others 

 maintained that they were supporting or contracting in function. 

 Yocom (1918) traced the fibrils to the motorium, a very small bilobed 

 body (about 8/i by 2^) located close to the right anterior corner of 

 the triangular cytostome (Fig. 17, a). Joining with its left end are five 

 long fibers from the anal cirri which converge and appear to unite 

 with the motorium as a single strand. From the right end of the 

 motorium extends the membranella-fiber anteriorly and then to left 



