1. Annelida

2. Annelids Characteristics –coelomates –Metamerism (= unspecialized segmentation) –In the Classes based on…  Parapodia  Clitellium

3. Systems IntegumentIntegument- epidermis is one cell layer with mucous gland that secrete a moist cuticle. SkeletalSkeletal -hydrostatic (using coelom) MuscleMuscle- longitudinal and circular muscles Each segments muscles are independent of the other segments. DigestiveDigestive- complete, complex, with typhlosole for absorption and chloragogen cells acting as digestive gland and excretory cells.

4. Systems, continued ExcretoryExcretory- a pair of nephridia per segment. RespiratoryRespiratory -through skin, some through parapodia; tubeworms have gills. CirculatoryCirculatory- closed system, use hemoglobin as oxygen carrier. NervousNervous- dorsal brain; ventral, double, solid nerve cord, with ganglia in each segment. EndocrineEndocrine- hormones secreted by nervous system. ReproductiveReproductive- –Dioecious in Polychaeta; no special organs, posterior end becomes gonads. –Monoecious in Oligochaeta and Hirudinea; Clitellium.

5. Annelid taxonomy Phylum Annelida (an-nel-i-da) –Class Polychaeta (poly-key-ta) Nereis, Aphrodita, Chaetopterus, Arenicola, AmphitriteNereisAphroditaChaetopterus, Arenicola, Amphitrite –Class Oligochaeta (ol-e-go-key-ta) Lumbricus, TubifexLumbricus –Class Hirudinea (hi-ru-din-e-a) Hirudo, leechHirudo Earthworm dissection

6. Nereis (clam worm) Nereis

7. Aphrodite (sea mouse) ventral dorsal

8. Other Polychaetes Arenicola (Lug worm) Chaetopterus Amphitrite (plum worm)

9. Hirudo (leech)

12. Earthworm cross section