 It is able to switch at will between the right or left kidney doing the bulk of the filtration, and can also regulate the filtration rate so that the rate does not increase when the animal's blood pressure goes up due to stress or exercise.Some species of octopuses, including "O. vulgaris", also have a duct that runs from the gonadal space into the branchial pericardium.Wells theorized that this duct, which is highly vascularized and innervated, may enable the reabsorption of important metabolites from the ovisac fluid of pregnant females by directing this fluid into the renal appendages.