title: Treatise Online no. 128: Part L, Revised, Volume 3B, Chapter 2: Systematic Descriptions of the Jurassic and Cretaceous Phylloceratoidea, Boreophylloceratoidea, and Aequiloboidea
abstract: Involute; compressed oval whorls with rounded venter, but a ventral keel developed in Carinophylloceras; with striae or fine to moderate ribs, and occasionally with radial undulations; weak constrictions only on inner whorls of some
journal: Treatise Online