what is the setae used for in worms
1 Every segment of a worm's body (except the first and last) has four pairs of tiny, stiff hair-like projections called setae. 2  To move forward, this is what a worm does: 3  First it grips the soil with some of its back setae so its back part can't move. 4  Then it squeezes its circular muscles, which makes its body get longer.