The poem is Martial, for all you D'Oogers and those not with a Wheelock:
Senos Charinus omnibus digitis gerit
Nec nocte ponit anulos
Nec cum lavatur. Causa quae sit quaeritis?
Dactyliothecam non habet!
Well, with some admiration for poetry you can definitely see the value of word arrangement. I guess the simple answer would be "for suspense." Textbook authors tend to ask questions to which they don't (understandably) expect an answer, but merely want you to ponder something...
flebile nescio quid queritur lyra, flebile lingua murmurat exanimis, respondent flebile ripae