|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|P. J. Noble and J. Maletz 2000||Spherical to subspherical shell consisting of two to three closely packed layers of loose labyrinthine mesh, long ro- bust tri-bladed primary spines most commonly seven to eight in number, with or without secondary spines. Some secondary spines are tri-bladed, others are flat blades.|