Animal Kingdom Classification: A Comprehensive Guide
Mollusks
Triploblasty, coelomates, not segmented. Bilateral symmetry. Soft body (head, visceral mass, foot). Limestone shell. Complete digestive tube (mouth-anus). Radula (in most). Open circulatory system (closed in cephalopods). Excretory system: 1 or 2 metanephridia. Ganglionic nervous system. Asexual or larval reproduction.
- Bivalves: Mussels
- Gastropods: Snails
- Cephalopods: Cuttlefish
Annelida
Triploblasty, coelomates. Bilateral symmetry. Elongated cylindrical body with rings or metamerism. Closed circulatory system. Ganglionic nervous system. Cutaneous respiration. Excretory system: metanephridia. Sexes separate or hermaphrodites. With or without a larval stage.
- Polychaetes: Marine worms
- Oligochaeta: Earthworms
- Hirudinea: Leeches
Arthropods
Triploblasty,...