Complex sentence: Its symbol was the bull (Latin: "Taurus"--holy animal of the goddess Venus, the mythical ancestor of the gens Julia), and this may mean that it was organized between 20 April and 20 May.
Split into simpler sentences: Its symbol was the bull (Latin: "Taurus", the holy animal of the goddess Venus and the mythical ancestor of the gens Julia). The symbol of Taurus may also mean that it was organized between 20 April and 20 May.