Platyhelminthes and Cnidaria
Echinodermata and Chordata: These are the only two phylums that are deuterostomes.
Platyhelminthes and Cnidaria: These two phylums are the only ones that use a gastrovascular cavity instead of digestive tract or diffusion.
Annelida and Chordata: These are the only two phylums with strictly a closed circulatory system. Annelida is the first phylum where this is present but this attribute then disappears until phylum chordata.
Porifera, Cnidaria and Platyhelminthes: None of these phylums have species with coelom.
Annelida and Chordata: These are the only two phylums with strictly a closed circulatory system. Annelida is the first phylum where this is present but this attribute then disappears until phylum chordata.
Porifera, Cnidaria and Platyhelminthes: None of these phylums have species with coelom.