Phoronopsis harmeri is a species of marine horseshoe worm in the phylum Phoronida.

Pixell in 1912, and was found off of Vancouver Island.

[2] This species has been found around the world in coastal habitats.

They have been known to various bacteria and other planktonic organisms with a size range of 1.2–12 μm.

[5] During larval development, serotonin-like immunoreactive parts of the nervous system change.