Trilobites were marine animals. Most have 30 or more legs with most body segments having two pairs per segment. The body, which is cylindrical, has short seven-segmented antennae and compound eyes. This structure is divided into many areas and is often used to identify different millipede groups. Millipedes generally reside in dark damp places such as in moss, under leaves, and in soil.
Some species give off a putrid fluid through openings in the body.
This fluid has been found to kill insects when placed in close vicinity to the millipede. While most millipedes are scavengers a few have been found to attack living plants and fewer still are predacious. These creatures overwinter as adults and their eggs are laid during the summer. Baby millipedes begin with only three pairs of legs and gain the others after several molts. Both are elongate and flattened, however, centipedes have only one pair of legs per body segments and have 15 or more pairs of legs.