From the literature we have drawnthe analogy between the
striated bundles presented here and the bundles in Tetrahymena.
Striated microfilament bundles in a contractile ring of
dividing ciliated protozoan Tetrahymena are situated beneath
the plasma membrane (Yasuda et al., 1980). The bundle in
Tetrahymena running parallel to the plasma membrane of the
ring consists of actin-like filaments and cross linkers attaching
to the membrane (Yasuda et al., 1980, 1984). It is an
interesting analogy that striated microfilament bundles having
relation with cytokinesis in both dividing Tetrahymena
and spermatogenic cells of the black snail consist of actin
(-like) filaments and cross linkers or bands.
The microfilament bundles attaching to the cytoplasmic
bridge membrane were occasionally (not always) observed
in spermatogonia, spermatocyte and spermatid populations,
as far as we examined. Percentages of a number