on the fifth day, before land animals.

_On the contrary,_ Suffices the authority of Scripture.

_I answer that,_ As said above, (Q. 70, A. 1), the order of the work
of adornment corresponds to the order of the work of distinction.
Hence, as among the three days assigned to the work of distinction,
the middle, or second, day is devoted to the work of distinction of
water, which is the intermediate body, so in the three days of the
work of adornment, the middle day, which is the fifth, is assigned to
the adornment of the intermediate body, by the production of birds
and fishes. As, then, Moses makes mention of the lights and the light
on the fourth day, to show that the fourth day corresponds to the
first day on which he had said that the light was made, so on this
fifth day he mentions the waters and the firmament of heaven to show
that the fifth day corresponds to the second. It must, however, be
observed that 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.

Reply Obj. 1: It was laid down by Avicenna that animals of all kinds
can be generated by various minglings of the elements, and naturally,
without any kind of seed. This, however, seems repugnant to the fact
that nature produces its effects by determinate means, and
consequently, those things that are naturally generated from seed
cannot be generated naturally in any other way. It ought, then,
rather to be said that in the natural generation of all animals that
are generated from seed, the active principle lies in the formative
power of the seed, but that in the case of animals generated from
putrefaction, the formative power of is the influence of the heavenly
bodies. The material principle, however, in the generation of either
kind of animals, is either some element, or something compounded of
the elements. But 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. 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