246 S. SAGUCHI 



tility, by virtue of which the ciHum is bent at that point ; hence 

 the rootlet acts as a support of the ciUum, while the transparent 

 zone holds the rootlet in its position; the restoration of the bent 

 cilium may be effected either by the elasticity of the cilium it- 

 self, or by the antagonistic action of the contractile substance. 

 It must be remembered, in this connection, that Eismond ('00) 

 compared the ciliary apparatus to the skeleton of the fin of a 

 bony fish, but I am far from agreeing with him in regarding 

 both the basal corpuscle and the rootlet as supporting organs 

 of the cilium. And, as the ciliary movement usually proceeds 

 in a determinate direction, it is natural that there should be 

 linear arrangement of the basal corpuscles in that direction. 

 With these conditions, a stimulation which causes the movement 

 of the cilia, is transmitted in a waving manner from one end to 

 the other of the same row, and thus the regular succession of the 

 ciliary movement is attained; this must be looked upon as being 

 most completely effected when all of the basal corpuscles of the 

 same row are fused, as in the corner-cells of gills of Anodonta; 

 the movements in different rows, on the contrary, are conceiv- 

 ably independent of each other. 



V. REGRESSIVE METAMORPHOSIS OF CILIATED CELLS 



A. TRANSFORMATION OF CILIATED CELLS INTO CELLS OF 

 DIFFERENT NATURE 



Historical. 



That ciliated cells become converted into glandular cells has 

 been observed by Knauff ('67), Flemming ('85), Osawa (97), 

 and others in the trachea, and by Lenhossek ('98) and Tschas- 

 sownikow ('13) in the pharnyx of Amphibia. All of these au- 

 thors state that droplets of secretion first appear above the 

 nucleus, which becomes pressed downwards with the increasing 

 accumulation of the former, so that at last there is formed a gob- 

 let or chalice cell. According to Lenhossek ('98) and Frenzel 

 ('86), even in such glandular cells, the ciha can still be preserved 

 and move actively. Next, the ciha are cast off and the secretion 

 is discharged. The casting off of the cilia, according to Brasil 



