* Atagema sp. (Kelaart, 1858) Figure 12C

Material examined.

One specimen 32 mm, CB.

Ecology.

Observed among rubble in shallow coral reef habitats at night with no observed association with prey. Depth 4-6 m.

Distribution.

Atagema sp. 8 (Gosliner et al. 2018) is known only from the Philippines.

Remarks.

Externally distinct from Atagema spongiosa (Kelaart, 1858) in being completely translucent pale grey, including the circular pits, separated by ridges, along the mantle. Similar to Atagema sp. 8 (Gosliner et al. 2018). Individuals from Koh Tao also differ from A. spongiosa in ecology, being observed in shallow reef environments instead of deeper soft sediment habitats.