Partectal ring



A bulbous chamber on the inside of the valvocopula. Found only in the genus Mastogloia. Usually arranged in a row on each side of the valvocopula, together forming the partectal ring. Plural form is partecta.

The partecta secrete mucilage to the outside of the diatom cell through relatively large pores, the partectal pores, in the wall of the valvocopula. These pores are connected to the partecta by the partectal ducts.

Alternative Term


A synonym for partectum.


An alternate term for partectum, used in some of the older literature (Stoermer et al., 1964).


Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Stoermer, E.F., Pankratz, H.S. and Drum, R.W. (1964). The fine structure of Mastogloia grevillei Wm. Smith. Protoplasma 59: 1-13.