Hill's Side-gill Slug

Pleurobranchus hilli

Pleurobranchus Hilli - Hill's Side-gill Slug
image_search Terms and anatomy

Size: 40 cm

Distribution: All SA continental waters

Habitat: Sandy bottoms. Common at the base of jetty piles

Depth: Lower intertidal to 10+ metres

This extremely large sea slug can occur up to 40cm in length, but is usually less than 20cm. It is dome-shaped, and covered in tubercles. A side-gilled sea slug (pleurobranch), it has no visible gills, although it does have rhinopores, which project through a frontal notch in the mantle. It can be found in either a uniform brown or maroon colour, or a paler orange-yellow colour, with tubercles ringed with maroon. Although distinctive, it has a similar shape to Psolidum sea cucumbers, which lack the tubercles and rhinophores. The rhinophores, as well as its large size also distinguishes this species from flatworms like those in the genus Thysanozoon.