The document introduces the phylum Annelida, or segmented worms. It notes that annelids can live in marine sediments, soil, or as parasites inside other organisms. They have a segmented body that allows separation of organ systems and bilateral symmetry. Annelids have a closed circulatory system, coelom, and separate mouth and anus. The document seeks an ideal mate that participates in external fertilization and has the key annelid traits. It cites several references used in the research.