Acta Palaeontologica Polonica

Cephalodiscus-type fibrils in the graptoblast fusellar tissue

Piotr Mierzejewski

Acta Palaeontologica Polonica 29 (3-4), 1984: 157-160

The fusellar tissue of an Ordovician graptoblast has been studied with TEM. It was found that It is solely composed of Cephalodiscus-type fibrils, unknown hitherto in graptolites. The fusellar tissue of the studied specimen has more in
common with recent pterobranchs than with graptolites.

Key words: graptolites, pterobranchs, ultrastructure, Ordovician.

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