Plate VII. Electron micrographs showing modifications of 

 the shaft structure of flagella and cilia. 



(a) Transverse section through the flagellar reservoir region 

 of Peranema. The two flagellar bases contain normal axial 

 bundles of fibrils and additional strands of intra-flagellar 

 material. > 28,000. 



{b) Transverse and longitudinal sections of the anterior 

 flagellum of Peranemo. Within the flagellar membrane is an 

 axial bundle of fibrils and additional intraflagellar material; 

 outside the membrane are two half-cylinders of striated material 

 as well as a zone of fine flimmer filaments. x 30,000. 



{a) and {b) from Roth (1959). 



(c) Transverse section of the collar region of a choanocyte 

 cell of the sponge Microciona. The flagellum carries two rows 

 of fine flimmer filaments in the plane of the central fibrils. 

 The additional structures on the left are sections of some of the 

 filaments that make up the collar. From Afzelius (1961b). 

 X 80,000. 



{d) Transverse section of the undulating membrane of 

 Trichomonas termidopsis. The axial bundle of fibrils is enclosed 

 with some additional material in an expanded flagellar membrane 

 which is attached to a fold of the cell membrane. The dense 

 striated structure within the body is a part of the costa. From 

 Grimstone (1961). 22,000. 



{e) Transverse section of a flagellum of Pyrsonympha vertens. 



Additional intraflagellar material is present outside each of the 



peripheral doublets, and is especially prominent on the side 



away from the body (at the top). From Grasse (1956). 



X 50,000. 



(/) Transverse section of the " undulating membrane " of 

 Blastocrithidia familiaris. This part of the flagellar structure 

 is not attached or adherent to the body of the trypanosome. 

 Note that the additional intraflagellar material is striated and in 

 the plane at right angles to the plane through the central fibrils. 

 X 51,000. 



ig) Transverse section of the " undulating membrane " of 

 Trypanosoma rhodesiense. The flagellar structure is here 

 adherent to the body surface, and the additional intraflagellar 

 material is again in the plane at right angles to the plane through 

 the central fibrils of the axial bundle. Note also the fibrils seen 

 in transverse section just beneath the body surface of the 

 trypanosome. X 52,000. 



Micrographs (/) and {g) by Vickerman. 



{h) The tips of two body cilia of Stentor polymorphus. The 

 basal region of the shaft has a normal diameter, as seen on the 

 left, but the terminal part is narrowed to form a " whiplash." 

 Original. x 8000. 



