MORPHOLOGY 57 



along the proximal border of the oral lip and the bases of all mem- 

 branellae. Yocom further noticed that within the lip there is a 

 latticework structure whose bases very closely approximate the cyto- 

 stomal fiber. Taylor (1920) recognized two additional groups of 

 fibrils in the same organism: (1) membranella fiber plates, each of 

 which is contiguous with a membranella basal plate, and is attached 

 at one end to the membranella fiber; (2) dissociated fiber plates con- 

 tiguous with the basal plates of the frontal, ventral and marginal 

 cirri, to each of which are attached the dissociated fibers (c). By 

 means of microdissection needles, Tajdor demonstrated that these 

 fibers have nothing to do with the maintenance of the body form, 

 since there results no deformity when Euplotes is cut fully two- 

 thirds its width, thus cutting the fibers, and that when the motorium 

 is destroyed or its attached fibers are cut, there is no coordination 

 in the movements of the adoral membranellae and anal cirri. 



A striking feature common to all neuromotor systems, is that 

 there seems to be a central motorium from which radiate fibers to 

 different ciliary structures and that, at the bases of such motor or- 

 ganellae, are found the basal granules or plates to which the "nerve" 

 fibers from the motorium are attached. 



Independent of the studies on the neuromotor system of American 

 investigators, Klein (1926) introduced the silver-impregnation 

 method which had first been used by Golgi in 1873 to demonstrate 

 various fibrillar structures of metazoan cells, to Protozoa in order 

 to demonstrate the cortical fibers present in ciliates, by dry-fixation 

 and impregnating with silver nitrate. Klein (1926) subjected the 

 ciliates of numerous genera and species to this method, and observed 

 that there was a fibrillar system in the ectoplasm at the level of the 

 basal granules which could not be demonstrated by other methods. 

 Klein (1927) named the fibers silver lines and the whole complex, 

 the silverline system, which vary among different species (Fig. 18). 

 Gelei, Chatton and Lwoff, Jirovec, Lynch, Jacobson, Kidder, 

 Lund, and others, applied the silver-impregnation method to many 

 other ciliates and confirmed Klein's observations. Chatton and Lwoff 

 (1935) found in Apostomea, the system remains even after the 

 embryonic cilia have entirely disappeared and considered it in- 

 fraciliature. 



The question whether the neuromotor apparatus and the silver- 

 line system are independent structures or different aspects of the 

 same structure has been raised frequently. Turner (1933) found that 

 in Euplotes patella (E. eurystomus) the silverline system is a regular 

 latticework on the dorsal surface and a more irregular network on 



