STUDIES ON CILIATED CELLS 255 



in the vertical direction ; the upper granule often bears a cilium, 

 thus forming the so-called ' Zentralgeisselzelle' of Zimmerman. 

 This is found not only in the efferent tubule of the mouse, but 

 also in that of the rat (fig. 89). 



In the efferent tubule of the rat, on the contrary, there are 

 no such typical centrosomes as above described, but instead 

 curious ring-shaped corpuscles in the transparent zone below 

 the cuticle (figs. 87, 88). Most of these rings have a smooth 

 internal and an uneven outer edge; in a certain sense they can 

 be spoken of as being formed by the apposition of granules. 

 Such rings are not always single, but there are many cells with 

 two, either of equal or of unequal size (fig. 87) ; in either case they 

 are arranged in a horizontal direction and connected with each 

 other by a fiber. 



I am inclined to beheve, from the position and staining of 

 these rings, that they are derived from the centrosomes; a cen- 

 trosome divides repeatedly and forms a ring by secondary 

 fusion of separated particles; the connecting fiber representing 

 the so-called 'centrodesmosis.' And, as a form of transition I 

 have found a cell with a ring and a granule, of which the latter 

 can be regarded as a component, still not divided, of the centro- 

 some. Whether the ' Zentralkorperballen' found by Benda 

 ('00) and Ikeda ('06) in the efferent tubule of the human testis 

 and my ring are of the same character or not remains uncertain, 

 but there are some differences between the two concerning the 

 shape and position. Moreover, these authors admit that the 

 'Zentralkorperballen' take part in the formation of the cilia, a 

 view with which I do not agree, for, on the one hand, the ciliated 

 cell with such rings is always in the fully developed state and, 

 on the other hand, it seems conclusive that the cihary apparatus 

 never originates from the centrosome, but from a certain other 

 constituent of .the cell, as will be afterwards described. 



As above described, Henneguy ('98), Lenhossek ('98), Joseph 

 ('03) and Fuchs ('02, '04) beheve that, in consequence of the 

 absence of the centrosome, mitotic division does not occur in 

 the ciliated cell. Ach ('02) and Tschassnowikow ('13) say that 

 no mitotic figure occurs in cihated cells in spite of the existence 



