Is the work of the fifth day fittingly described?
Dixit etiam Deus: “Pullulent aquae reptile animae viventis, et volatile volet super terram sub firmamento caeli”.
Creavitque Deus cete grandia et omnem animam viventem atque motabilem, quam pullulant aquae secundum species suas, et omne volatile secundum genus suum. Et vidit Deus quod esset bonum;
benedixitque eis Deus dicens: “Crescite et multiplicamini et replete aquas maris, avesque multiplicentur super terram”.
Et factum est vespere et mane, dies quintus.
(Gen 1:20-23)
Yes. The words, "Let the waters bring forth the creeping creature having life, and the fowl that may fly over the earth," fittingly describe this work because at the first beginning of the world the active principle was the Word of God, which produced animals from material elements, either in act, as some holy writers say, or virtually, as Augustine teaches.
Convenienter dicitur, "producant aquae reptile animae viventis, et volatile super terram," quod in prima autem rerum institutione, fuit principium activum verbum Dei, quod ex materia elementari produxit animalia vel in actu, secundum alios sanctos; vel virtute, secundum Augustinum.
Not as though the power possessed by water or earth of producing all animals resides in the earth and the water themselves, as Avicenna held, but in the power originally given to the elements of producing them from elemental matter by the power of seed or the influence of the stars.
Non quod aqua aut terra habeat in se virtutem producendi omnia animalia, ut Avicenna posuit, sed quia hoc ipsum quod ex materia elementari, virtute seminis vel stellarum, possunt animalia produci, est ex virtute primitus elementis data.
Augustine differs from other writers in his opinion about the production of fishes and birds, as he differs about the production of plants. For while others say that fishes and birds were produced on the fifth day actually, he holds that the nature of the waters produced them on that day potentially.
Alii enim dicunt pisces et aves quinta die esse productos in actu, Augustinus autem dicit, V super Gen. ad Litt., quod quinta die aquarum natura produxit pisces et aves potentialiter.