Sunday, September 11, 2011

introdduction of Mollusca with classes


Mollusca(soft body animals)
            The animals with soft body enclosed in shell produced by them are called Mollusca.There are four classes of the Mollusca. They are
1)    Aplachophora or solenogasters
These are mollusca which are without head,mantle,foot ,shell and nephridia.
  (A=not+plax=plate+pherein=bearing)
2) Polyplacophora        
                        These are mollusca which are provided with shell formed by longitudinal series of eight calcareous pieces.
          ( poly=many+plax=plate+pherein=bearing)
3) Monoplacophora                                   
                   These are mollusca which are provided with shell formed by single piece of calcareous piece.
(Mono=single+plax=plate+pherein=bearing)
4)    Gastropoda  
                         These are mollusca provided with foot on visceral mass.
(Gaster=belly+podos=foot)
5)scaphopoda 
   Theseare mollusca provided with boat shaped  foot.
   ( scapha=boat+podos=food)
6)Pelecypoda
 These are mollusca which are provided by shells with two 
  lateral valves,swinging together mid darsoventrally.(Pelekys=hatchet+podos=foot)
7)Cephalopoda
These are mollusca which are provided with reduced shell embeeded in mantle
(kephal=head+poda=foot)

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