Head upon shoulder
U 10.657-8: Are you trying to imitate your uncle John [...] head upon shoulder?
The expression “head upon shoulders” has nothing to do with the old proverb about a wise (or old) head upon young shoulders. Simon is simply saying "Dilly, don't hunch your shoulders so that your neck disappears from view and it looks like your head is set immediately upon your shoulders." Later Stephen notices "Dilly's high shoulders and shabby dress" (U 10.855).
This seems to be another case of Joyce reaching back into the recent past to find an expression that suited his text.
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