fenestrate

"Observation on the development of some fenestrate sporidia".

The live creature had a delicate calcareous lattice structure representative of fenestrate growth forms, but in most fossils these latices have been destroyed, leaving only the spiral backbone.

Columbellopsis nycteis, common name : the fenestrate dove shell, is a species of sea snail, a marine gastropod mollusk in the family Columbellidae, the dove snails.