There, Sacculina, unlike other barnacles,
sheds her outer shell and injects herself into the crab.
Mature Sacculina can live as long as their hosts, and,
therefore, continue to breed for at least one or two years.
There, many tiny male Sacculina in larval form(the males never reach adult maturity)
enter the female's external sac and fertilize her eggs, of which she can make hundreds every day.