 Palpata has become superfluous with the elevation of Canalipalpata to subclass.Palpata includes the majority of genera and species of polychaete worms and is subdivided into the orders Aciculata and Canalipalpata.The prostomium is characterised by a pair of sensory palps which gives the subclass its name and which are lacking in the other main taxon of polychaetes, the Scolecida.