Tuesday, November 22, 2011

Orders of subclass3-PULMONATA


The subclass 3-Pulmonata has only two orders namely as follows.
Order 1:-BASOMMATOPHORA
  Order 2:-STYLOMMATOPHORA


Order 1:-BASOMMATOPHORA 
          1) They are found in marine water, freshwater and brackish
              water.
          2) They have delicate shell with a conical spire and large
               aperture.
         3) They have one pair of non-invaginable tentacles with the   
          eyes at their bases.
         4) The male and female gonopores are generally separate.
               Examples:- Siphonaria, Lymnaea, Planorbis
ventral surface of Siphonaria
Siphonaria in garden


Dorsal structure of Siphonaria                                          
planorbis
Lymnaea
Lymnaea



































Order2:-STYLOMMATOPHORA
       1) They are terrestrial pulmonates.
         2) They have shell with a conical spire, internal or absent.
         3) They have two pairs of invaginable or retractile tentacles
             with the eyes at the tips of the posterior pairs.
         4) They have male and female gonopores usually united.
             Examples:- Limax, Helix, Partula, Retinella.


limax


Partula

Retinella.


              

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