Circulation time, blood reserves and extracellular space in a cephalopod

Abstract

Octopus vulgaris Cuvier has a fully enclosed blood system that includes large blood sinuses behind the eyes and around the gut. It would be useful to know the mean circulation time, the minimal number of heartbeats needed for blood to return to the hearts, and/or the extent to which the sinuses constitute a reserve of blood which can be mobilized in times of stress. Experiments are reported in which aortic pulse and pressure are recorded using a cannula following injection of inulin.