In Mark Twain's essay "How to Tell a Story," what does Twain say is the difference between telling a humorous story and telling a comic story?

In his essay "How to Tell a Story," Mark Twain says that
the difference between telling a humorous story and telling a comic story is has to do
with whether the teller acts like he thinks the story is funny or not. In his
estimation, telling a humorous story, which is a distinctly American skill, is "strictly
a work of art...only an artist can (do) it." The humorous story must be "told gravely;"
the teller hides the fact that he even suspects that there is anything funny about it.
It might "be spun out to great length, and may wander around as much as it pleases," and
the listener must be alert for the "nub," or point of the story, because in many cases
the teller will drop it in a way that is "carefully casual and indifferent...with the
pretense that he does not know it is a nub."

On the other
hand, the teller of the comic story is very clear that he is about to tell "one of the
funniest things he has ever heard." In Twain's opinion, comic stories are uniquely
British, and, in contrast to the humorous story, anyone can tell them. Twain describes
the comic story as being brief, and always ending with a nub. The teller is very clear
in identifying the nub of his story, and may repeat it again and again if it is received
positively.

Twain does not hold back in expressing his
disdain at the primitiveness of the comic story; to him, the humorous story requires
much more skill to tell effectively, to the point that he elevates it to an art. It is
not accident that he emphasizes the American roots of the humorous story, which, in a
tongue-in-cheek manner expresses his opinion that the American way is far superior to
the British tradition.