galaxies' disks have coalesced together but the nuclei have not. Centaurus A (Arp 153) and NGC 1316 (Arp 154) are both effectively elliptical galaxies with unusual dust lanes; their kinematics and structure indicate that they have undergone merging events recently. NGC 4747 (Arp 159) may be nothing more than an edge-on spiral galaxy with a significantly dark dust lanes. Diffuse filaments The filaments in these objects may represent tidal tails from galaxy interactions. Many of the galaxies are the remnants of the mergers of two spiral galaxies to form a single elliptical galaxy. However, NGC 3414 (Arp 162) appears to be merely an unusual S0 galaxy with a very small disk relative to its bulge size. NGC 4670 (Arp 163) is a blue compact dwarf galaxy with extremely strong star formation activity; it is clearly too small to be the merger remnant of two spiral galaxies like the other merger remnants in this sample, although it may have been involved in a much smaller interaction. Diffuse counter-tails All of these objects are galaxies involved in gravitational interactions. These counter-tails are tidal features caused by the gravitational interactions between two galaxies, just like similar features described in the Arp catalog. Messier 32 (Arp 168), a dwarf galaxy interacting with the Andromeda Galaxy, is included in this category (although the "diffuse counter-tail" is very difficult to see in Arp's photograph). Narrow counter-tails This is another category containing galaxies with tidal tails produced by gravitational interactions. These tidal tails are narrower and better defined than the tidal tails in objects 167–172. Narrow filaments This category contains a mixture of different types of objects. Like the galaxies with diffuse filaments or galaxies with counter-tails, some of the galaxies in this category have been involved in interactions, and the filaments are tidal features created by those interactions. Other sources, however, are simply individual spiral galaxies with faint spiral arms that are described as "filaments" by Arp. Material ejected from nuclei The ejecta in many of these objects appear to be tidal features created by gravitational interactions. In some cases (such as for NGC 5544 and NGC 5545 in Arp 199), the "ejecta" are clearly a spiral galaxy viewed edge-on that happens to line up with another galaxy's nucleus. Almost all of the objects in this category are interacting or have recently undergone interactions. NGC 3712 (Arp 203) is an exception; it is merely a low