Drawing

Description:

Calliacantha natans (Groentved, 1956) Leadbeater, 1978. Choanoflagellates with a conical lorica, 25 - 27 microns long and with six longitudinal and two transverse costae. One transverse costa is located at the top of the lorica chamber, the other is shortly below it, but is formed of thinner costal strips and may be difficult to see. Three spines project from the top of the lorica and a single posterior spine. The anterior spines are not continuous with the longitudinal costae.