What I see, with my old eyes, is a possible mid merger of two
spiral galaxies.

My guess is the following:
The denser galaxy appears to be coming in at about 60 degrees
to the plane of the other. The center of the denser galaxy has not
yet reached the plane of the other galaxy (or maybe it is already passed
through it). All that I see of the weaker galaxy is the outer edge.
Here is an illustration.