Appearance
Anthopleura ballii has a broad base up to 5 cm (2 in) across and a trumpet-shaped column up to 10 cm (4 in) high. The surface of the column bears forty-eight longitudinal rows of small warts, each tipped with red. The oral disc is wide and there are up to 96 tapering tentacles arranged in five whorls. These are retractable to a limited extent and are flecked with white. The colouring of this species is variable, being some shade of red or yellow, with the tentacles sometimes having an iridescent green sheen. The warts are non-adhesive. This is in contrast to the closely related glaucous pimplet (Anthopleura thallia), which has gravel or debris adhering to the column.

