226 CILIATE FIBRILLAR SYSTEMS 



tions is confined primarily to morphological evidence. This evidence is 

 derived, however, not only from their studies on the fibrillar system of 

 Paramecium, but also from comparative studies of a considerable number 

 and variety of other ciliates. 



According to von Gelei's interpretation, Klein's strongly birefringent 

 "indirekt System" (Meridian II. Ordnung) is nothing more than the 

 well known "pelliculare Gittersystem" of the ciliates, which functions 

 as a supporting network to maintain body form. As such, it has no 

 differentiated structural connections with the less refractive inner fibrillar 

 complex (von Gelei's neuroneme system), which alone, therefore, is 

 the peripheral conductive mechanism. Von Gelei sees in the longitudinal 

 and transverse fibrils of his neuroneme network a mechanism which 

 structurally integrates the ciliary basal granules, the trichocysts, and even 

 the contractile vacuole pore into a coordinated whole ("einer koordi- 

 nierten Einheit"). 



This integrated mechanism coordinates automatically the metachronous 

 effective strokes of successive cilia. The direction of the stroke of one 

 cilium activates conditionally that of the next by way of the basal 

 apparatus (basal granule, basal ring, and "Nebenkorn"), which repre- 

 sents a sensory organelle. For the coordinated activity of the organism 

 as a whole, however, von Gelei recognizes in his peripheral neuroneme 

 system the absence of a neuromotor center. Accordingly, he regards the 

 "intraplasmatic" fibrillar complex described by Rees as a centralized 

 mechanism which may complement the peripheral neuroneme complex, 

 thus to provide reasonably a unified neuromotor system. Von Gelei 

 (1929b) observed by means of his silver-osmium-formol method a 

 "platte" beneath the basal apparatus, which, he thought, might serve 

 as a sort of end plate connecting Rees's intraplasmic fibrils with the 

 peripheral neuroneme complex. 



As has been previously indicated, Klein's (1926-32) interpretation 

 of his inner fibrillar complex (Meridian I. Ordnung) agrees essentially 

 with von Gelei's concept of a conductive function for his peripheral 

 neuroneme network. Among their minor differences, Klein would ac- 

 count for the commonly observed reversal in the effective stroke of cilia, 

 not by means of Rees's intraplasmic complex as von Gelei supposed, but 

 by way of a "primitive reflex arc." This reflex arc includes the axial 

 filament of the cilium as the receptor, the basal apparatus as the ""relator," 



