Invertebrate
animal without a vertebral column
Ctenophora
Platyhelminthes
Orthonectida
Placozoa
Rhombozoa
Arthropoda
Bryozoa
Phoronida
Hemichordata
Acanthocephala
Brachiopoda
Rotifera
Nemertea
Porifera
Gastrotricha
Chaetognatha
Sipuncula
Entoprocta
Cnidaria
Annelida
Echinodermata
Gnathostomulida
Cycliophora
Kinorhyncha
Loricifera
Priapulida
Nematomorpha
Onychophora
Tardigrada
sea slug