Name those phyla in which circulatory system is open and body cavity is filled with blood.

Open circulatory system:

1. The phyla in which the circulatory system is open and the body cavity is filled with blood are present in Mollusca and Arthropoda.
2. Open circulatory systems work by pumping blood into a hemocoel.
3. The species in the phylum Arthropoda have an open circulatory system.
4. Mollusca have open circulatory systems like a snail, chiton, slug, etc, except for cephalopods which have closed circulatory systems.