Download - class Clitellata
PRESENTED BY:
HINA AMIR
Class Clitellata• Include earthworms and leaches.
Symplesiomorphic Characters:
1. Clitellum for cocoon formation.
2. Few or no setae.
3. Monoecious
Subclass Oligochaeta
• 3,000 species• Aquatic as well as terrestrial.• Include earthworms.
External Structure
• Few Setae.• Prostomium having small lobe.• Clitellum.• Cuticle.
.
Locomotion
• Antagonism of circular and longitudinal muscles.
• Burrowing ……..Coelomic hydrostatic pressure.
Feeding and digestive system
• Scavenger .• Depend on fallen and decaying vegetation. Digestive system:• Tubular and straight.• Mouth Pharynx crop gizzard calciferous
gland Anus• Typhlosole.
Gaseous exchange and Circulation• Respire through body wall. CIRCULATION• The blood system is a closed system.• Blood…..head to the tail in the ventral vessel tail to the head….. in the dorsal vessel• Photoreceptors are present
Nervous system
–Dorsal brain–Pair of nerves on sides of esophagus–Paired ventral nerve cords with paired
ganglia in each segment–Transverse nerves connect ganglia in
each segment
Excretion: Metanephridia
Reproduction:
• Monoecious. Sexual reproduction• Through copulation….. cocoon formation.
Asexual reproduction• Transverse division• Regeneration of parts