The fine structure of cell surface and hair-like projections of Filipodium ozakii Hukui 1939 gamonts

The ultrastructure of the cell surface and the hair-like projections of Filipodium ozakii gamonts was studied by TEM and SEM. The surface of the entire body of F. ozakii was covered with the regular longitudinal folds along the body axis and hair-like projections. The deep and shallow grooves alternately separated the folds and the hair-like projections which originated at the bottom of every 2nd or 4th groove. The inner and outer membranes at the cell periphery and longitudinal microtubules under the inner membrane were observed. The structures of the cell surface were similar to those of Selenidium fallax which have been previously described. The appearance of projections resembled cilia or flagella but their ultrastructure was completely different and characteristic not having the typical arrangements of 9 + 2 microtubules inside the projections.