Spiral Varieties

With reference to the inner structure of galaxies, the manner in which the spiral structure terminates is a valid classification parameter [27]. If the spiral arms continuously circle into the nucleus ``(s)'' is suffixed to the stage and family classification. If the spiral structure ends in a ring structure ``(r)'' is added. Transition cases ``(rs)'' are also found. For more details, see also LB, NS, Vol. VI/1, p. 668.