Boy, have I missed you guys.
I usually see these referred to as "scallop" or "scalloped" cancels, though I've seen them described on
ebay as "wavy" cancels. They are courrier conveyeur cancels, which for this purpose can be thought of as railway post office cancels. I can't explain the technical difference.
If they have the construction with an "a" between two destinations, they are a cancel for a particular route; they can also appear as just the station.
I have some interesting ones, including West Africa and Madagascar. I'll scan a few when I get a minute.
Collin