Actinocerids are generally straight-shelled nautiloid cephalopods with a siphuncle composed of expanded segments, typically with thin connecting rings, in which the internal deposits are penetrated by a system of canals.

Actinoceratids are derived from Wutinoceras, possibly through an early Armenoceras or through Nybyoceras[2] and give rise to Lambeoceras and to the Huroniidae.

[citation needed] Seven genera are included in the Actinoceratidae, Actinoceras, Floweroceras, Kochoceras, Leurorthoceras, Paractinoceras, Saffordoceras, and Troostoceras.

Paractinoceras has a long, straight, slender shell and a siphuncle that starts off like that in Actinoceras, but becomes narrow like that in Ormoceras in the anterior part of the phragmocone.

[1] Kochoceras has a large blunt shell that expands more rapidly than Actinoceras and is strongly flattened on the ventral side causing possible confusion with Lambeoceras to casual observation.