From proto- + nephridial. <span class="searchmatch">protonephridial</span> (not comparable) Relating to a protonephridium relating to the protonephridium...
protonephridia) (anatomy) A type of nephridium composed of a network of flame cells or solenocytes. metanephridium <span class="searchmatch">protonephridial</span> a type of nephridium...