Figure 3-39-C.

Liquid stalling a little further inside entrance to a chamber.

The contact angle on all surfaces is 53 degrees, so Concus-Finn filaments do not form form. When the liquid tips reach the entrance to the bulge, there is a brief pause at the sharp corner until the floor contact line makes it just into the bulge, so the filament tip can make it around the corner. But the filaments cannot continue much beyond the corner, just a bit more than for a contact angle of 54 degrees.