Scanning electron microscopy of the ventricular surface of the paraventricular organ in the domestic fowl.

The ventricular surface of the paraventricular organ in the domestic fowl is covered with supraependymal fiber elements. These fibers from a dense network having a web-like appearance and a coarse network of fibers running over the ventricular surface. The dense, web-like networks are mainly distributed throughout the caudal region of this organ, whereas the course networks are observed in the rostral region. In addition to these structures, spherical bodies with diameters approximately 2.5 to 6 micron are also encountered.