Six words and no gloss. One Homeric verse is copied out1 — as one tragic verse was at 11.30. Toward the end of Book XI such bare quotations run almost continuously: the notebook has gone over into a mode of gathering material, and what exactly Marcus meant to do with it he does not write.
What is in the line. φίλον κῆρ — "dear heart," the Homeric formula for one's own insides (φίλος in Homer often means simply "one's own"). And the verb ἐγέλασσε: it is not the man who laughs but the heart in him. The verse describes exactly the state for which Marcus has no term: not joy as a good motion, nor pleasure, but a brief inward triumph with no outward expression at all.
Why it might have been wanted. The Homeric context suggests a use, though Marcus does not name it: Odysseus keeps silent and laughs to himself at the most dangerous moment — when any betrayal of himself would cost his life. For a man whose every act is on view (cf. 11.27: a star has no προκάλυμμα, no "screen"), this is a rare note about an unexpressed inner state: not everything that happens within is obliged to come out.
The neighbourhood. The next passage, 11.32, is also a single line, but from Hesiod and with the opposite sign: there virtue is reviled. The two excerpts, on laughter and on abuse, stand side by side with no connective; to connect them is already the reader's business. The governing discipline is assent, the sustaining one desire.