Permoceratidae

The Permoceratidae is a small family of nautiloids, restricted to the Permian, apparently derived from the Grypoceratidae. This family is represented by a single genus, Permoceras, which comes from the lower Permian of the East Indies. Shells are involute, earlier whorls covered, compressed so as whorls are highter than wide, and smooth. The outer rim, or venter, is rounded, as are umbilical shoulders. The siphuncle is ventral of the center but not marginal.

Pseudonautilus from the Jurassic, is similar to Permoceras, with much the same configuration.