Hemiphragmoceratidae is a family of endogastrically brevconic oncocerids characterized by elaborately visored apertures in which the hyponomic sinus in mature specimens is on a spout-like process and there may be lateral and dorsal salients. (Sweet 1964, Flower 1950). Shells are compressed with the apical portion curved and the anterior straight. Siphucles are nummuloideal with expanded spheroidal segments and continuously actinosiphonate interiors. Some five genera have been described; Hemiphragmoceras, Contradoceras, Hexameroceras, Octamerella, and Tetrameraoceras.