Language: Bilingual in English and Polish
Volume 4 lists a large number of invertebrate classes:
- Porifera
- Cnidaria
- Anthozoa
- Scyphozoa
- Ctenophora
- Monogenea
- Trematoda
- Cestoda
- Rotatoria
- Bdelloidea
- Gastrotricha
- Nematoda
- Acanthocephala
- Mollusca
- Priapulida
- Bryozoa
- Polychaeta
- Oligochaeta
- Hirudinea
- Tardigrada
- Pentastomida
- Crustacea
- Arachnida
- Acari
- Opiliones
- Pseudoscorpionida
- Chilopoda
- Diplopoda
- Pauropoda
- Symphyla