As soon as I posted this question, I realised.
The sunapton was not an adjective sunaptos, but the participle sunapto^n of sunapto^.
The place in the Googlebooks.
https://play.google.com/store/books/det ... AAJ&rdot=1
(Iamblichus' De Mysteriis)
The paragraph 2
Ti to sunapton esti pros aso^matois theois tous echontas so^ma en to^i ourano^i ?
The Latin translation displayed in the same page is thus :
Quid sit quod cum diis incorporeis deos in caelo corporeos connectat ?
(What would be that which connects the corporeal gods in heaven with the incorporeal gods ?)
By the Latin I understand the meaning, but I don't clearly see the grammatical structure of the Greek.
(Is this an omittion of the infinitive of sunaptomai ? Can the infinitive of verbs other than einai be omitted ?) Someone please explain to me.