- Phylum Porifera
"sponges" - Scypha
- Phylum Cnidaria
- Class Hydrozoa
- Hydra
- Obelia
- Class Scyphozoa "true jellyfish"
- Class Anthozoa
- Class Hydrozoa
- Phylum Ctenophora "comb jellies"
- Phylum Platyhelminthes "flatworms"
- Class Turbellaria : Planaria
- Class Monogenea "flukes" - Gyrodactylus with opisthaptor
- Class Tremotoda
"flukes"
- Schistosoma mansoni cercaria "blood fluke"
- Fasciola hepatica "sheep liver fluke" adult,
cercaria
- Class Cestoda "tape worms" - Taenia pisiformis
- Phylum Nematoda "roundworms" - Trichinella spiralis encysted in muscle
- Phylum Rotifera
- Phylum Mollusca
- Class Gastropoda
- Class Polyplacophora
- Class Bivalvia
- Class Cephalopoda
- Phylum Annelida "segmented worms"
- Class Polychaeta "sandworms"
- Class Clitellata
- Subclass Oligochaeta "earthworms"
- Subclass Hirudinea "leeches"
- Phylum Onychophora "velvet worms"
- Phylum Arthropoda
- Subphylum Trilobita
- Subphylum Chelicerata
- Class Merostomata
- Class Arachnida
- Subphylum Mandibulata
- Class Crustacea
- Class Entognatha, Order Collembola "springtails"
- Class Diplopoda "millipedes"
- Class Chilopoda "centipedes"
- Class Insecta
- Phylum Bryozoa - Bugula
- Phylum Echinodermata
- Class Stelleroidea
- Subclass Asteroidea "starfish"
- Subclass Ophiuroidea "brittlestar"
- Class Echinoidea "sea urchin"
- Class Holothuroidea "sea cucumber"
- Class Stelleroidea
- Phylum Hemichordata "acorn worms"
- Phylum Chordata
- Subphylum Urochordata "sea squirts" or "tunicates" - Ascidian tadpole
- Subphylum Cephalochordata - Amphioxus
"lancelet"
- Subphylum Craniata