What does Jack Merridew wear in the beginning of the novel? What happens to his clothing?

Jack Merridew is introduced as being covered "from throat to ankle" with a black cloak, which sported a "long silver cross on the left breast." He was the leader of the choir boys and uniformed as such. Over the course of the novel, we saw Jack lose the uniform and all civility. His disappointment over Ralph's election to leadership, leads him to take his boys and set himself up as leader in a new and different way. Each time he tried to regain full power, he would change just a bit more, until finally he totally resembled the savage he became.