In many sources - and in this score - this work is listed as Op.35.
Op.35 however belongs to "Les Djinns". See the composer's work list.
BNF has a "Op.35 3 nocturnes for voice and piano" which it several times confuses with Op.35 Les Djinns in its original (Feb. 1915?) voice/piano form (if the very confusing BNF catalog can be unknotted)... checking the worklist and perhaps also one of the resource books on Vierne does seem a good idea here thanks... - ESh