Calcareous plates in barnacles of the superorder Acrothoracica, morphologyand functions, homology with calcareous plates of barnacles of the superorder Thoracica (Thecostraca, Cirripedia)

Calcareous plates were found in the shallow-water species Lithoglyptes miti s and L. habei. Their morphology is similar to the same plates on deep-wate r lithoglyptids. The plates are located in the area of the attachment disk and are covered with a thin membrane-like cuticle with tiny cuticular papil lae-like structures. These structures probably secrete a peculiar cement fo r the attechment of animal to host. The homology of these calcareous plates of thoracicans is discussed. The calcareous plates of acrothoracicans and the attachment disk are shown to be homologous to the basal area of thoraci cans.