How do the hirudineans differ from the polychaetes and oligochaetes?

Explanation

1) Definite number of body segments are present in hirudineans but many segments are present in polychaetes and earthworms.
2) Locomotion in leeches is by suckers but body setae in oligochaetes and parapodia in polychaetes. Parapodia also help in respiration.
3) Temporary clitellum during breeding season in present in leeches but clitellum is absent in polychạetes and permanent clitellum is present in oligochaetes.
4) Hirudineans are bisexuals, oligochaetes are bisexual and polychaetes are unisexual animals.
5) Coelom is reduced on leeches, but coelom is spacious in oligochaetes and polychaetes.
6) Development is direct in leeches and earthwarm but indirect in polychaetes.
7) Nutrient tissue called botryoidal tissue fills the coelom in hirudineans.
8) Anterior and posterior suckers are present in hirudineans. Such suckers are absent in polychaetes and oligochaetes,