See text Heteractinida is an extinct grade of Paleozoic (Cambrian–Permian) sponges, sometimes used as a class or order.

They are most commonly considered paraphyletic with respect to Calcarea (calcareous sponges),[1][2][3] though some studies instead argue that they are paraphyletic relative to Hexactinellida (glass sponges).

[4] Heteractinids can be distinguished by their six-pronged (snowflake-shaped) spicules, whose symmetry historically suggested a relationship with the triradial calcarean sponges.

[4] The sponge-like Cambrian Hetairacyathidae may be related to heteractinids,[5] though most instead consider hetairacyathids to be closer to archaeocyaths and radiocyaths.

It has an intact skeleton of felted sexiradiates of three orders of spicules.