Electron Microscopic Study on the Arterial System in Lamprey Gill, with Special Reference to the Fine Structure of Gavernous Body

The cavernous body in the gill of the lamprey, Lampetra planeri, was studied with scanning (SEM) and transmission (TEM) electron microscpes. It became clear by means of SEM observation of the blood vascular cast of gill, using Mercox resin, that the cavernous body runs along the long axis of afferent filament arteries branching from an afferent branchial artery. Furthernore, the cavernous body was divided into 2 parts, a central sinusoid and bilateral reticular capillary containing one marginal capillary. The latter is a vascular component of the gill lamella. It appeared that all of the blood flowing into the respiratory region of the gill must pass through the cavernous body.