SECONDARY PIT CONNECTIONS
Click here for the primary pit connections. Another kind of cell connection is the cell fusion.

	RECENT	FOSSIL
S E M		(from: Braga et al. (1993): Palaeontology vol. 36)	S E M
	Secondary pit connections (arrows) connect cells of adjacent filaments (longitudinal section).	In fossil material (SEM) the original cell walls are leached; both cell lumina and secondary pit connections (arrow) are filled with cement (transversal section).
	Secondary pit connections are not known from thin section, until now.