Ophioceras is a genus of closely coiled tarphycerid nautiloid cephalopods, the sole representatives of the family Ophidioceratidae, characterized by an evolute shell with narrow, subrounded, annulated whorls and a subcentral siphuncle composed of thin connecting rings that show no evidence of layering.

[2] Ophioceras has a narrow, evolutely wound, closely coiled shell that diverges in the adult stage.

The shell is more or less circular in cross section, strongly annulate with close spaced, rounded, transverse ribs.

The adult aperture has deep hyponomic and ocular sinuses, not too dissimilar from the Ordovician Lituites, to which this genus is possibly allied.

Minor evolutionary changes can be observed within both species, which In spite of their widespread distribution do not demonstrate any major geographical variations.