CLASSIFICATION 415 



Phylum 5. NEMATHELMINTHES: Round Worms. Ascaris, 

 Trichina. (1500 species.) 



Phylum 6. TROCHELMINTHES: Rotifers. (500 species.) 

 Phylum 7. MOLLUSCOIDA: Polyzoans and Brachiopods. (2000 

 species.) 



Phylum 8. ECHINODERMATA: (4000 species.) 



Class I. ASTEROIDEA: Starfishes. 



Class II. OPHIUROIDEA: Serpent Stars. 



Class III. ECHINOIDEA: Sea Urchins. 



Class IV. HOLOTHUROIDEA: Sea Cucumbers. 



Class V. CRINOIDEA: Feather Stars, Sea Lilies. 

 Phylum 9. ANNELIDA. Segmented Worms. (4000 species.) 



Class I. ARCHIANNELIDA : Polygordius. 



Class II. CHAETOPODA: Earthworms, Clamworms. 



Class III. HIRUDINEA: Leeches. 

 Phylum 10. MOLLUSCA. (60,000 species.) 



Class I. LAMELLIBRANCHIATA : Oysters, Clams, Scallops, 

 Shipworm. 



Class II. AMPHINEURA: Chiton. 



Class III. GASTROPODA: Snails. 



Class IV. SCAPHOPODA: Dentalium. 



Class V. CEPHALOPODA: Squid, Octopus, Nautilus. 

 Phylum 11. ARTHROPOD A. 



Class I. CRUSTACEA: Barnacles, Crayfishes, Lobsters, Crabs, 

 Trilobites (extinct). (16,000 species.) 



Class II. ONYCHOPHORA: Peripatus. 



Class III. MYRIAPODA: Centipedes, Millipedes. 



Class IV. INSECTA: Locusts, Bugs, Flies, Butterflies, Beetles, 

 Ants, Bees, Wasps. (400,000 species.) 



Class V. ARACHNIDA: Scorpions, Spiders. (16,000 species.) 

 Phylum 12. CHORDATA. 



Subphylum A. ENTEROPNEUSTA: Dolichoglossus. 

 Subphylum B. TUN 1C AT A: Tunicates. Cynthia. (1500 



species.) 

 Subphylum C. CEPHALOCHORDA: Amphioxus. 



