Poetry collections are traditionally "slim volumes" i.e. selective! Mercier may have simply added additional material due to the much wider interest in Clifford when they did the reprint. It's a pity they didn't spell out the alterations, alright.

I think I may have a copy of the Comhaltas article I mentioned earlier - which would have predated the Mercier reprint IIRC. It may have some detail - I'll have a look for it when I get a chance.

BTW I asked about the Table of Contents because "The Boys.." was not the original title.