CILIATE FIBRILLAR SYSTEMS 223 



behavior was not demonstrated by the writer's (1920) experiments. 

 Reinvestigation of this problem, especially on a more favorable form 

 such as Lkhnophora (Stevens, 1891), ought, therefore, to be undertaken 

 in order to determine what relative roles the so-called introplasmic fibrils 

 and the peripheral fibrils each perform in the coordinated movements 

 of the organelles with which such fibrils are demonstrably associated. 



Several investigators (Belar, 1921; Jacobson, 1931; Peschowsky, 

 1927) have maintained that all such cirri fibrils in the hypotrichous 

 ciliates and the fibrillar systems in various other ciliates are primarily 

 or exclusively supporting in function. Jacobson (1931), for example, 

 studied by means of various techniques, including the silver-nitrate 

 methods, the fibrillar systems of some twenty-seven ciliates. These com- 

 prised representatives of all the major groups and included among the 

 hypotrichs £. patella and £. char on. She concluded from the results that 

 no evidence was found in support of a conductive function for any of 

 the fibrillar systems studied. It was pointed out that in the hypotrichs 

 whose motor organelles are localized, fibrils are nevertheless present, 

 as on the dorsal side where cilia are wanting. Reference on this point 

 should be made to Turner's (1933) studies on £. patella, which showed, 

 as previously mentioned, that longitudinal fibers connect the bases of 

 the dorsal and ventral rows of bristles, whose function is not known. 

 But they may have a function and if that function is, as has been 

 suggested, sensory in nature, it is surely not inconceivable that the 

 associated fibrils may facilitate its performance. 



Another and more significant observation was made by Jacobson, viz., 

 that in Sciadostoma difficile, where three ciliary rows surround the 

 anterior body pole, no silverline connection exists between the basal 

 granules. An impulse, therefore, originating at the anterior ciliary ring 

 would need to pass nearly to the posterior body pole and back again in 

 order to affect adjacent cilia. Since our assumptions should be, first of 

 all, plausible, one would justifiably regard this morphological evidence 

 contradictory to the thesis that these silverlines in 5". difficile are con- 

 ductive in function. It may be pointed out, however, that Chatton and 

 Lwoff (1935) apparently demonstrated that the fibrils (cinetodesme) 

 described for several holotrichous cihates, which alone were connected 

 with the basal granules, could not be stained by silver impregnation, 

 whereas other adjacent fibrils (interpreted by them as silverline fibrils) 



