Activity 20_ Ppt Phylum Annelida

PHYLUM ANNELIDA

Annelids     

Segmented worms Made up of somites/segments/metameres Bilaterally symmetrical Tripoblastic Eucoelomates - have a true coelom 

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Body cavity lined with peritoneum

Mouth is anteroventral Anus is posterodorsal NERVOUS SYSTEM with brain and ganglia May be monoecious or dioecious

Class Polychaeta    

Mostly marine Have most primitive members Segments have parapodia with setae Head has well developed eyes and tentacles

Class Oligochaeta  

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Head not well developed Body without parapodia but with setae Have a glandular citellum (special segment)

Class Hirudinea   

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Leeches Fixed number of segments Segmentation incomplete; externally divided by annuli Have anterior and posterior suckers Hermaphroditic Citellum at segments 9 and 10 Genital pore in segment 11

Nereis ( clamworm)Class Polychaeta

Nereis (clamworm) Dorsum

Venter

Sabella (fan worm/ feather duster worms) Class Polychaeta radioles

Aphrodita (sea mouse)Class Polychaeta

Pheretima (earthworm)Class Oligochaeta

Life cycle of Earthworm

Lumbricus (earthworm)Class Oligochaeta

Parts of Lumbricus

Hirudo (Leech)Class Hirudinea

Anatomy of Leech

Macrobdella- Class Hirudinea

Kiitos