This ring takes the form of a spiral and ends in a snake's head.
Roman jewellery borrowed heavily from Hellenistic goldwork. This particular type was common in Hellenistic times, especially in Egypt.
Snakes were the symbol of a number of deities associated with healing, including the Egyptian goddess Isis and the Greek god of medicine Asclepios. It was therefore a commonly used pattern in jewellery, its spiral shape lending itself well to rings and necklaces. Worn as an amulet, the snake protected its wearer.