* Marianina rosea (Pruvot-Fol, 1930) Figure 22C

Material examined.

One specimen 10 mm, CB.

Ecology.

Under rubble, among small hydroids, in coral reef habitats. Depth 5-8 m.

Distribution.

Across the Indo-Pacific including India (Apte 2009), Australia (Burn 1978), South Africa, Madagascar, the Philippines, Papua New Guinea, and New Caledonia (Gosliner et al. 2008). Here representing a first record for Thai waters.

Remarks.

The single specimen observed from Koh Tao appears paler than is typical for the species, though such colour differences are not unheard of (see Fraser 2000). It is clearly recognised by its cerata and rhinophoral morphology, unique among the Tritoniidae .