 Tarphyceras

Tarphyeras is a genus of tarphyceratid with whorls rounded in cross section, having a deeply impressed dorsum and a ventral to subcentral siphuncle, known from the Lower Ord (U Canad) of North America.It differs from "Campbelloceras" in that "Campbelloceras" is only slightly impressed, from "Centrotarphyceras" in that "Centrotarphyceras" is subquadrate and has a central siphuncle, and from "Trocholites" in that although "Trocholites" is subcircular in cross section, the siphuncle is subdorsal.