Tags: Crustacean.
Thecostraca are a subclass of marine invertebrates containing about 1320 described species. Many species have planktonic larvae which become sessile or parasitic as adults.The most important subgroup are the barnacles (infraclass Cirripedia) constituting about 1220 known species.The subgroup Facetotecta contains a single genus Hansenocaris known only from the tiny planktonic nauplii called y-larvae.
