''Thyca'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of small

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusks Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The num ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Eulimidae Eulimidae is a family of very small parasitic sea snails, marine gastropod mollusks in the superfamily Vanikoroidea. Description These small parasitic snails live on (or in some cases in) the bodies of echinoderms such as sea cucumbers, se ...

.Bouchet, P. (2012). Thyca H. Adams & A. Adams, 1854. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=196298 on 2012-07-25 These snails are

ectoparasites Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...

starfish Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, ophiuroids, which are correctly referred to ...

; 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.G.W. Tryon (1886) Manual of Conchology v; VIII
/ref>

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)

References

* Habe T. (1976) ''Parasitic gastropods from echinoderms of Japan''. Bulletin of the National Science Museum okyo ser. A, 2(3): 157-171. 2 September 1976page(s): 165 * Warén A. (1980). ''Revision of the genera Thyca, Stilifer, Scalenostoma, Mucronalia and Echineulima (Mollusca, Prosobranchia, Eulimidae).'' Zoologica Scripta 9: 187-210 * Warén A. (1984) ''A generic revision of the family Eulimidae (Gastropoda, Prosobranchia)''. Journal of Molluscan Studies suppl. 13: 1-96. page(s): 46 {{Use dmy dates, date=May 2017 Eulimidae