Phylum COELENTERATA 



Individual or colonial forms; two cellular body layers present; radially 



symmetrical; digestive tract sac-like; usually with tentacles; with 



stinging cells or ncmatocysts 

 Phylum PLATYHELMINTHES 



Bilaterally symmetrical, dorso'ventrally flattened, unsegmented worms; 



no coclom; digestive tract sac-like; wuth cilia 

 Phylum NEMATHELMINTHES 



Cylindrical, unsegmented worms; without cilia 

 Phylum ROTATORIA 



Usually with a ciliated disc anteriorly; with mastax or internal jaws; 



with coelom 

 Phylum BRYOZOA 



Colonial; with tentacles on a ridge around the mouth; digestive tract 



U-shaped; with coelom 

 Phylum ANNELIDA 



Segmented worms; with setae in the body wall or with a sucking 



disc on the posterior end of the body; with coelom 

 Phylum MOLLUSCA 



Body soft, unsegmented; usually with a shell: sometimes with 



tentacles 

 Phylum ARTHROPODA 



Body segmented; usually w'lth a chitinous exoskeleton; appendages 



paired, jointed 

 Invertebrates of uncertain position 



NEMERTEA 



Unsegmented; with a long, eversible proboscis; digestive tract tubular; 



no coelom (Often grouped with Phylum Platyhelmmthes) 



GASTROTRICHA 



Unsegmented; somewhat flattened dorso-ventrally; ciliated below; 



digestive tract tubular; with coelom (Often paired with the Rotatoria. 



under Phylum Trochelmmthes) 



TARDIGRADA 



With fused segments; appendages paired, unsegmented; (Grouped 



with Phylum Arthropoda in this book) 

 Vertebrates 

 Phylum CHORDATA 



Possessing, at some stage in development, a notochord or backbone,, 



pharyngeal gills or lungs, and a dorsal, tubular nervous system 



Class CYCLOSTOMATA 



Mouth round, without jaws; no bones; no paired appendages^ 

 cold-blooded 



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