Invertebrate
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Invertebrates are animals that neither develop nor retain a vertebral column, which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum Ver
The fossil coral Cladocora from the Pliocene of Cyprus
Coral Outcrop Flynn Reef
Tracheal system of dissected cockroach. The largest tracheae run across the width of the body of the cockroach and are horizontal in this image. Scale bar, 2 mm.
Annelid
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Annelids, also known as segmented worms, are animals that comprise the phylum Annelida. The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist i
This sabellid tubeworm is budding
Burgessochaeta setigera
Phylogenetic tree of early lophophorates
Regenwurm 1