Although nearly all other crustaceans have separate sexes, most barnacles are hermaphrodites, with cross-fertilization between adjacent individuals being the rule. Some species, however, have dwarf males, which are parasitic on female or hermaphroditic individuals. The fertilized egg develops into a free-swimming larva, called a nauplius larva, of the basic crustacean type, with paired antennae. This form then molts to become a cypris, or bivalve, larva, which eventually attaches itself to a suitable substrate by its first pair of antennae and undergoes metamorphosis into an adult.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.