NGC 3351. - Seven very intense emission regions are found in the center of this galaxy. They all appear brighter than the nucleus itself and define an elliptical ring of semimajor axes about 7". The very dark central dust lanes emerge from this ring of HII regions and wind outward. The western lane disappears but the eastern is quite strong and can be followed as it branches and bends to join the outer broken ring of this galaxy. The inner structure of the galaxy is well illustrated in plate 27 of Morgan's paper (1958). The major axis of the inner HII ellipse makes an angle of about 40° with the line defining the dust "bar," which in turn "leads" the stellar "bar" by about 35°. The major axis of the outer ring coincides approximately with that of the inner HII ellipse.

The HII regions identified in the outer ring are very much fainter than those in the nucleus. Their extreme faintness and the lack of an off-H photograph makes this identification uncertain. No sketch is given of this galaxy.