What is the cephalochordate caecum compared with in vertebrates?

In cephalochordates, the caecum is a structure through which blood passes to facilitate the uptake of nutrients. It is functionally compared to the liver of lower vertebrates, as blood makes a similar detour through the liver in those animals to process nutrients before returning to the ventral aorta.1

It is important to note that this cephalochordate caecum is distinct from the cecum found in many vertebrates, which is a pouch-like structure at the beginning of the large intestine primarily responsible for absorbing fluids and salts or aiding in the digestion of plant matter.2