The early development of the cement apparatus in the barnacle, Balanus balanoides (L.) (Crustacea: Cirripedia)

The development of the cement cells of Balanus balanoides (L.) has been followed over a 26-day post-settlement period. Cells of the cyprid cement glands de-differentiate to form part of the juvenile barnacle apparatus, but the majority of juvenile cement cells develop by differentiation of collecting duct cells. These latter cement cells are recognized by apical invaginations which are continuous with the collecting duct lumen. Collecting ducts are present in the cyprid. The cement duct system was not studied in detail, but preliminary observations of the arrangement in B. balanoides and Elminius modestus Darwin have shown them to differ, the system in E. modestus being simpler.