The Benedictine Editor adds the two last words τύπον παραδηλοῦν from mss. Roe. Casaub. as necessary to the construction, and adds the following note.  “The text thus emended is capable of two senses.  The first, that the Holy Spirit came down in the form of a dove, a pure and harmless bird, to shew that He is Himself as it were a mystic dove in His simplicity and love of children, for whose new birth and remission of sins at Baptism He unites His prayers with Christ’s, as Cyril teaches in Cat. xvi. 20:  and that Christ was for the like cause mystically foreshown in Canticles as having eyes like a dove’s.  The other sense is, that the Spirit descended in the form of a dove on Christ’s Humanity in order to shew this to be as it were a dove in innocence, holiness, love of children, and concurrence with the Holy Spirit in their regeneration.…Either sense is admissible, and maintained by many of the Fathers:  but I prefer the former.”  This interpretation is confirmed by Tertullian (de Baptismo, c. viii.), who says that the Holy Spirit glided down on the Lord “in the shape of a dove” in order that the nature of the Holy Spirit might be declared by means of a creature of simplicity and innocence.”