De generibus et speciebus  

"Thus "Socratitus" is merely an accident of the substance "humanitas," or, as it is put by the author of the treatise De generibus et speciebus," Man is a species, a thing essentially one (res una essentialiter), which receives certain forms which make it Socrates." --EB1911[1]

In the Isagoge of Porphyry, translated by Boethius, which until the thirteenth century was the common text-book of logic in the schools, the following passage occurs: Mox de generibus et speciebus, illud quidem .

"I shall omit to speak about genera and species, as to whether they subsist (in the nature of things) or in mere conceptions only; whether also if subsistent, they are bodies or incorporeal, and whether they are separate from, or in, sensibles, and subsist about these, for such a treatise is most profound, and requires another more extensive investigation". --Porphyry on the problem of universals in the Isagoge, translation by Boethius, English translation quoted in A History of Western Philosophy (McInerny and Caponigri), p. 357, Ralph McInerny, ‎Aloysius Robert Caponigri