The word Monoplacophora is derived from three Greek words monos=one, plax=plate and pherein=bearing. So it includes animals having only one plate. It does not have any order.The characteristics of it are listed as below.
1) They have bilaterally symmetrical and segmented body.
2) They have shell made up of single piece or valve.
3) They have head without eyes and tentacles.
4) They have ventral and flat foot.
5) They have mantle which encircle the body as a circular fold of the body wall.
6) They have external and serially arranged gills.
7) They have five pairs of serially arranged nephridia.
8) They have sex organs in two separate bodies.
Examples :- Neopilina galatheae