Sessilia
Sessilia is an order of barnacles, comprising the barnacles without stalks, or acorn barnacles. They form a monophyletic group and are probably derived from stalked barnacles. The order is divided into three suborders. The Brachylepadomorpha contain a single family, Neobrachylepadidae, while the Verrucomorpha contain two families, Verrucidae and Neoverrucidae. The remaining 12 families are in the suborder Balanomorpha.
