Narial is one word - but doesn't seem to fit?
nare
n () a nostril, esp a hawk's.
[L n\-aris, pl n\-ar\-es, nostril]
nares n pl (; ) the nostrils.
narial or narine adj of or relating to the nostrils.
n\-aricorn n a horny termination of a bird's nostril
Yes - sorry paulineward - my comments were meant for mintoff who as you say had an extra blank before the 'L'. Your first post was not there when I posted and as I do not do that particular crossword was not aware that narial would fit the clue. Near simultaneous postings cause this problem sometimes, don't they - but my apologies to you nonetheless.