In a paragraph here omitted occur these words, which are of interest in the discussion of evolution. "The order of the sentient to the intelligent, and of the vegetative to the sentient, is as the order of potentiality to actuality: for the intelligent is posterior in generation to the sentient, and the sentient to the vegetative: for animal is prior in generation to man." St Thomas is here describing the development of the individual, as Chap. LXXXVI shows, not of the race; or what is now called 'ontogenetic' as opposed to 'phylogenetic' development.
Of God and His Creatures: 2.58