Crystalline Sea Star Snail

Thyca crystallina

Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Littorinimorpha
Family: Eulimidae
Genus: Thyca
Species: Thyca crystallina

The crystalline sea star snail (Thyca crystallina) is a small parasitic snail with a cap-shaped shell, found clinging to sea stars. Its colour often matches its host.

It attaches permanently to the arm of a blue sea star and feeds by inserting its proboscis into the host's tissues.

In the Philippines it is found by checking blue Linckia sea stars on shallow reefs.