Characteristics of mollusca class APLACOPHORA

The word Aplacophora is derived from three words a=not,plax=plate and pherein=bearing. Thus this class includes animals without plate. It has two orders namely

Order 1:- Neomenioidea

Order 2:- Chaetodermatoidea

 The characteristics are listed in points as follow.

  1) They have bilaterally symmetrical, cylindrical and worm like 
      body.

  2) They do not have head ,mantle, foot, dhell and nephridia.

  3) They have body covered with cuticle beset with numerous 
      calcareous

      Spicules.

       4) They have mouth and anus which are terminal or sub terminal at opposite

             ends.

   5) They generally have straight digestive tract  with a radula.

   6) They have a pair of coelomoducts in the form of gonoducts 
         opening into

       The terminal part of intestine or independently.

   7) They have a mid-dorsal longitudinal keel or crest.

    8) They may have sexes in the same body ( hermophrodite) 
        or may have in separate body( dioecious)