Research study 5
drawings of antennule with details of attachment disc on the cyprid larva of a barnacleAt the end of each antennule of the cyprid is a disc surrounded by a curtain-like velum. Clustered on each disc are cuticular bristles, sensory hairs, and glandular openings. As it explores the sea bottom, the larva “walks” on its antennule tips. At each “step” it is thought that proteinaceous enzymes are released from the glandular openings that allow chemical identification of the substratum surface. The curtain-like velum is believed to isolate the chemical reactions from outside seawater dilution. Crisp et al. 1985 J Colloid Interface Sci 104: 40.
NOTE the velum is not shown in the "attachment organ" drawing below