PHYLUM ANNELIDA. Segmented worms usually -with well-developed ccelom and metamerically segmented nephridia. 

 Canalicular vascular system. Nervous system with cerebral ganglia, otsophageal ring and ventral nerve-cord with 

 a ganglionic swelling in each segment. 



Class i. CH^TOPODA. Annelida with bristles (chaetse) secreted in pits of the ectoderm and serving as organs of 

 locomotion. 



Order i. OLTGOCH&TA. Chsetopoda without parapodia or tentacles : hermaphrodite with localised generative 



organs. Development direct. 



Sub-order i. Terricolse. Ex. Lumbricus, Allolobophora. 

 Sub-order 2. Limicolse. Ex. Nais, Tubifex, Chatogaster. 



Order i. POLYCH.STA. Chsetopoda with chsetae generally arranged in bundles and carried on outgrowths 

 of the body wall (parapodia). Head with tentacles and palps : the sexes are separate and the 

 generative products are developed from the ccelomic wall throughout the body. Generally with 

 a Trochosphere larva. Ex. Nereis, Aphrodite, Eunice free-swimming forms : Terebella, Arenicola, 

 Filograna tubicolous forrns. 



Class 2. HIRUDINEA. Annelida without chsetse and parapodia, moving by means of a terminal ventral sucker, the 

 mouth acting as an anterior sucker, and living on the juices of other animals; ccelom much reduced 

 hermaphrodites with direct development. 

 Order i. RHYNCHOBDELLIDJE. Ex. Clepsine, Pontobdella. 

 Order i. GNATHOBDELLID.E. Ex. Hirudo, Nephelis. 



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