What did the Greek sailor, Scyllis, use to breathe underwater in 500 BC?

Century old artifacts suggest that people would dive for pearls and other materials.  Greek literature offers much information about early sponge divers.  In fact, in 500 BC, Herodotus tells a story about a Greek sailor named Scyllis who was able to breathe by using a hollow reed as a snorkel while he was underwater cutting the lines of Persian ships.