Thoracica
Thoracica is an infraclass of crustaceans which contains the most familiar species of barnacles found on rocky coasts, such as "Semibalanus balanoides" and "Chthamalus stellatus". They have six well-developed limbs, and may be either stalked or sessile. The carapace is heavily calcified. The group includes free-living and commensal species. Classification. This article follows Chan et al. (2021) and WoRMS in placing Thoracica as an infraclass of Thecostraca and in the following classification of thoracicans down to the level of family: