The centipedes and millipedes belong to two separate classes.  The centipedes and millipedes body is divided into many segments and each segment consist of a single pair (centipede) or two pairs (millipede).  The centipedes don't have 100 legs and neither millipede have 1000 legs as their names imply. 

The millipedes have rounded bodies unlike centipede’s flat bodies.  Millipedes are herbivores and centipedes are carnivores.   These animals have a bilateral symmetry and are terrestrial.