Situational Irony: Active Mind versus Inactive Body
If bothered by a strange and hitherto absent mark on the wall, most people would simply get out of their seat and see what it was. The woman does not do this. Her mind is running a marathon of possibilities, visiting different historical periods, considering the meaning of life, and wondering about prior inhabitants of the house, but her body is ironically still, as she is oddly not motivated to get out of her chair to see what the mark is. As fast as her mind moves, her body does not move at all.
Dramatic Irony: Husband's Identification of the Mark
The woman spends a long time considering what the mark might be and philosophizes at length about it. By contrast, her husband is in the room for less than a minute and is able to identify the mark as a snail.
Situational Irony: Overanalyzing without Remembering
The woman decides that the mark is actually a nail hole that was left after a picture was taken down. The irony of this is that, for all of her philosophizing and thinking, she does not remember for some time that she has never actually hung a picture up there.
Verbal Irony: An Answer without Closure
At the end of the story, the narrator's husband flippantly, unknowingly, answers the question that the narrator has been pondering throughout the story: the mark on the wall is a snail. Ironically, however, the overall epistemically skeptical tenor of the story leaves the reader uncertain as to whether the mark really is a snail, despite the fact that the mark's identity has been identified in what one might imagine is the most straightforward way possible. This invites the question: is there any ending to the story that could really leave us satisfied that we really know what the mark is?
