rURBELLA RIANS. 



149 



B. 

 C. 



D. 



TuRBELLARiA. Planarians, 

 Trematoda. Flukes, etc. 

 Cestoda. Tapeworms, etc. 



Nemertea. Ribbon worms. 



Nematoda. Thread worms 

 ing the Gordius type. 



etc. j Plathelminthes, 

 \ Scolecida, or 

 I Flat-worms. 



includ- 





Nemathel- 

 minthes. 



AcANTHOCEPHALA. Echtnorhynclius. ) Round worms. 



CHjEtopoda. Bristle-bearing worms. 



Oligochaeta. ^.^., Earthworms. 

 Polychaeta. Marine worms. 

 Echiuridae. eg., Echiurus I Annelids 

 and Bonellia (sometimes \ or 

 called Gephyreans). /" Ringed 



Appended to Chaetopoda are — I Worms. 



( 1 ) Primitive forms — Archi-annelida. 



(2) Myzostomata — parasitic on Crinoids. 

 DiscoPHORA or Hirudinea. Leeches. 



E. Provisionally appended to the Annelid series — 



Chaetognatha. Arrow- worms. SagittaznASpadella. 

 Rotatoria. Rotifers. 



F. There remain — 



Sipunculoidea, Sipunculus, etc. 

 (sometimes included with Ech 

 iuridae as Gephyreans). 



Phoronidea. Phoronis. 



Polyzoa or Bryozoa. Sea Mats, etc. 



Brachiopoda. Lamp-shells. 



\ 

 J 



Perhaps 



related to 



one another. 



First Series. 

 FLAT-WORMS OR 

 PLATHELMINTHES- 



Class TuRBELLARiA, Plan- 



arians, etc. 

 Class Trematoda, Flukes, 



etc. 

 Class Cestoda, Tapeworms, 



etc. 



Class TuRBELLARiA. Planarians, etc. 



The Turbellarians are simple " worms " living in fresh, 

 brackish, or salt water. Many of them are called Planarians. 



