Schematic illustration of the apical structure in Perophora annectenns.
The plasma membrane enclosing the anterior quarter of the apical structure is decorated by the anterior ornaments (AO).
A helical string (HS) can beobserved running inside along the ridge of the helix.
Fluff (FL) is present on the plasma membrane just outside the region corresponding to the helical string.
A, B and C are views inside the anterior, middle andposterior regions, respectively.

J. Cell Sci. 66, 175-187 (1984).

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