Ocellulimbus

An ocellulimbus is a type of porefield found on a valve apex. Externally, the ocellulimbus appears to be set into the apex of the valve. Like other porefields, the ocellulimbus likely secretes mucopolysaccharides which are used to attach the diatom to a substrate or to sibling cells. From Latin for little eye (ocellus) and border (limbus). The plural is ocellulimbi.

Ocellulimbi are found in several araphid genera such as Catabombas, Ctenophora, Pseudostaurosira, Synedra, and Tabularia.

Williams (1986) defined ocellulimbus as a "plate set into the polar valve mantle".

See ocellus, porefield, and pseudocellus for more detail.

Citations

Williams, D.M. and Round, F.E. (1986) Revision of the genus Synedra Ehrenb. Diatom Research 1: 313-339
Williams, D. M. (1986) Comparative morphology of some species of Synedra Ehrenb. with a new definition of the genus. Diatom Research, 1 (1): 131-152

Ocellulimbus — Scanning electron micrographs of two valves of *Pseudostaurosira parasitica*. An ocellulimbus is present at each pole.

Ocellulimbus External — External view of the ocellulimbus of *Stauroforma inermis*. Material from the Thames River estuary, Connecticut.

Ocellulimbus Internal — Internal view of the ocellulimbus of *Pseudostaurosira parasitica*.