Cells solitary or colonial. Cell 3.5-5.5 x 4.5-7 microns, flagellum 13-19 microns long surrounded by a collar of tentacles ~8 microns long. Lorica conical, ~8 microns long, consisting of a single transverse costa at the anterior of the lorica, and 8-10 longitudinal costae. The transverse costa consists of 10 or 11 slightly curved costal strips, one of which is duplicated. The longitudinal costae have no regular means of attachment to the transverse costa; joints may be in the middle or at the ends of the transverse costal strips. Longitudinal costae undergo numerical reduction, so that three to eight strips form the 'handle' at the posterior of the lorica. All costal strips are narrow rods. Division is tectiform.