Saturno is shown in his less flattering form, eating his children. As the Roman god of harvest was often taken for the Greek God Chronos, he was seen as the keeper of time, and he holds an Ouroborous as the symbol of recreation and ternity. The scythe, usually seen as a grim allegory of death, is also a symbol for harvest, for renewed hopes and rebirth. It stands for both a beginning and an end.
Compare with XXXII - Chronico
Further reading: Saturn (Planets)