Later observations seem to show that the H II region forms a ring around the nucleus and that prodigious star formation is occurring in the galaxy. A rather unusual effect is seen in the spiral structure of this galaxy. The arms show several sudden changes of direction at sharp angles, producing an over-all polygonal structure, and there is an exceptionally bright and thick star cloud in the arm on the north edge of the system. Italian astronomer B. Oriani discovered M-61 in May 1779, while observing the comet of that year. Messier found it a few nights later and at first mistook it for the comet.
Many faint arms are present on the outside of the two bright ones.
The many knots in the brighter arms are undoubtedly HII regions.