Cells solitary; lorica barrel-shaped, divided into 2 chambers by waist that marks point of attachment of lorica to protoplast; anterior chamber longer than posterior chamber consisting of longitudinal costae terminating anteriorly in a transverse costa; one or more transverse costae encircle anterior chamber; posterior chamber formed by longitudinal and transverse costae usually forming oppositely directed spirals; protoplast located in posterior chamber and base of anterior chamber; simple pedicel or an aggregated pedicel may be present; division tectiform; in salt and brackish water, particularly stagnant water