Thyca

Thyca is a genus of small sea snails, marine gastropod mollusks in the family Eulimidae. These snails are ectoparasites of starfish; they are relatively unmodified, the underside having become a suction disc with a central mouth that draws nourishment from the host's tissues.

Description
The conical shell is longitudinally grooved, transparent and slightly curved.

Species
Species within the genus Thyca include:
 * Thyca astericola (A. Adams & Reeve, 1850)
 * Thyca callista Berry, 1959
 * Thyca crystallina (Gould, 1846)
 * Thyca ectoconcha P. Sarasin & F. Sarasin, 1887
 * Thyca hawaiiensis Warén, 1980
 * Thyca lactea (Kuroda, 1949)
 * Thyca nardoafrianti (Habe, 1976)
 * Thyca sagamiensis (Kuroda & Habe, 1971)
 * Thyca stellasteris Koehler & Vaney, 1912
 * Species brought into synonymy:
 * Thyca pellucida Kükenthal, 1897 : synonym of Thyca crystallina (Gould, 1846)