PLATYHELMINTHES TURBELLARIA 



Classification of Tricladida. 



PALUDICOLA. 



Family. Genus and British Species. 



PLANARIIDAE . . Planaria lactea 0. F. M. , P. punctata Pall. , P. polychroa 



Schm., P. torva M. Sch., P. alpina Dana. 

 Polycelis nigra Ehr., P. cornuta Schm. 

 Anocelis. 



Oligocelis. \Doubtful 

 Procotyla. /genera. 

 Sorocelis. 

 Dicotylus. 



MARICOLA. 



PROCERODIDAE . . Procerodes (= Gunda) ulvae Oersted, P. littoralis van 

 ( = Gundidae). Beneden. 



Cercyra. 



Uteriporus. 

 BDELLOURIDAE . . Bdelloura. 



Syncoelidium. 



TERRICOLA. 



BIPALIIDAE . . Bipalium kewense Moseley (introduced). 

 GEOPLANIDAE . . Geoplana. 



Geodesmus. 

 RHYNCHODEMIDAE . Rhynchodcmus terrestris O. F. M. 



f Dolichoplana. 



Belonging to undeter-J Polycladus. 

 mined Families | Microplana. 



I Leimacopsis. 



TurbeUaria. III. Rhabdocoelida. 



The Rhabdocoelida include a very heterogeneous assemblage of 

 usually minute TurbeUaria, distinguished collectively from the 

 Polyclads and Triclads by the form of the digestive tract. This 

 is a simple or slightly lobed sac, except in the Bothrioplanidae, 

 which in this and many other points closely resemble the 

 Triclads. It is to the straight, rod-like nature of the alimentary 

 canal that the name of the group refers. The size and form of 

 the body, and the structure of the pharynx and genitalia, vary 

 within wide limits. 



The Rhabdocoelida are subdivided into three tribes : 

 (1) Acoela, in which a sub-central mouth and pharynx are 

 present, but lead into the parenchyma of the body, not into an 

 intestine with proper walls. An excretory system has not 

 hitherto been seen. Yolk-glands are absent. An otolith under- 

 lies the brain. The Acoela are marine. 



