Striatocycloceras undulostriatum (Hall, 1847)

Diagnosis. Slightly curved, slightly compressed Striatocycloceras with very low apical angle of approximately 2°.Adult dorsoventral diameter approximately more than 30 mm, with four to six annulations at a distance that equates the corresponding shell diameter in adult. Annulations slightly oblique, irregularly spaced, with faint lobe at the sidein opposition of the siphuncle. Distinct growth lines, 10––12 per cycle of annulations, one or two cycles of annulations per chamber. Suture lines run slightly oblique in relation to annulations forming a slight sinus at the side opposite to the siphuncle. Siphuncle subcentral. Short, orthochoanitic septal neck.