Spiral-Galaxy with multiple arms and a closed elliptic Dark-Cloud-Ring in the central area and several branchings at the outer side of the Galaxyarms.
The flattened lower part of the Acceleratorring forms out a Mainstream and a Branchstream for a long period. The top part of the Acceleratorring has much more camber and forms out only a Mainstream. In the theory of the development of Spiral-Galaxies it is explained, how do the Galaxyarms and their Branchstreams develop. Look also for the black-white-photo from the Galaxy NGC1365.