A sacoglossan to about 5 cm (2 in) whose back is crowded with flattened leaf-shaped cerata, each veined with fine pale lines, so that a resting animal reads as a small clump of weed rather than as a slug. Color runs green to brown depending on what it has been eating.
The cerata are both camouflage and defense: they detach when the animal is attacked and go on moving, and they hold the chloroplasts drained from algal cells, which keep photosynthesising inside the slug. Feeding is done with a radula reduced to a single tooth per row - the sacoglossan solution to a diet of cell contents rather than tissue, and the reason the whole group is confined to a handful of green algae. Nocturnal and well hidden, it is one of the harder members of the group to find on these reefs.
- back crowded with flattened leaf-shaped cerata
- green to brown with fine pale veining on each ceras
- cerata shed readily when disturbed
- length up to 5 cm
