PHYLUM PLATYHELMINTHES. Flat worms without an anus. Excretory system as fine canaliculi ending in flame- 

 cdls. Generative organs complicated and generally provided with vitellaria. Hermaphrodite. No body cavity or vascular 

 system. 



Class i. TURBELLARIA. Free-living Platyhelminthes covered with cilia: with muscular protrusible pharynx. 



Classified according to the structure of the alimentary canal. 

 Order i. ACCELA. Gut solid. Ex. Convoluta. 



Order 2. RHABDOCCELA. Gut hollow, rod-shaped. Ex. Mesostoma. 



Order 3. TRICLADA. Three main branches to gut. Generative opening single. Ex. Dendrocalurn. 

 Order 4. POLYCLADA. Numerous branches to gut. Generative opening double. Ex. Thysanozoon. 



Class 2. TREMATODA. Parasitic Platyhelminthes with suckers and hooks and forked alimentary canal. Without 



cilia. 



Order i. MONOGENEA. Trematodes with direct development. Ex. Polystomum. 

 Order 2. DI6ENEA. Trematodes with alternation of hosts. Ex. Distomum. 



Class 3. CESTODA. Parasitic Platyhelminthes with suckers and hooks on the head, and a chain of sexual proglottides 

 breaking off when ripe ; no mouth or alimentary canal. Ex. T<znia, Bothriocephalus. 



