Haeckel
Diagnosis: Shell broadly ovate to nearly circular in lateral view, lenticular, with a variable number of marginal spines of variable shape. Peristome helmet-shaped or half conical, longer than shell radius, with 2 pairs of conical, curved, divergent teeth. Terminal teeth are the halves of a forked dorsal tooth, diverging laterally. Lower teeth nearly horizontal and directed ventrally.
Diameter: 0.13-0.15 mm.