(διαιρεθείη δ’ ἂν καὶ ἕκαστον τού(2)των εἰς εἴδη πάλιν, οἷον τὸ πεζὸν καὶ τὸ πτηνὸν καὶ τὸ (3) ἔνυδρον.)
ἔσται οὖν κἀκεῖνα ἅμα τῇ φύσει, ὅσα ἐκ τοῦ αὐτοῦ (4) γένους κατὰ τὴν αὐτὴν διαίρεσίν ἐστιν·
τὰ δὲ γένη τῶν εἰ(5)δῶν ἀεὶ πρότερα·
οὐ γὰρ ἀντιστρέφει κατὰ τὴν τοῦ εἶναι (6) ἀκολούθησιν·
οἷον ἐνύδρου μὲν ὄντος ἔστι ζῷον, ζῴου δὲ ὄντος (7) οὐκ ἀνάγκη ἔνυδρον εἶναι.
(8) —ἅμα οὖν τῇ φύσει λέγεται ὅσα (9) ἀντιστρέφει μὲν κατὰ τὴν τοῦ εἶναι ἀκολούθησιν,
μηδαμῶς δὲ (10) αἴτιον τὸ ἕτερον τῷ ἑτέρῳ τοῦ εἶναί ἐστιν,
καὶ τὰ ἐκ τοῦ αὐτοῦ (11) γένους ἀντιδιῃρημένα ἀλλήλοις·
ἁπλῶς δὲ ἅμα, ὧν ἡ γένεσις ἐν (12) τῷ αὐτῷ χρόνῳ.
(15) Diuiditur autem et unumquodque eorum in species iterum secundum eandem (16) diuisionem, ut gressibile animal et uolatile et aquatile.
Erunt igitur (17) et illa simul natura, quaecumque ex eodem ipso genere secundum eandem (18) subdiuisionem sunt,
genera autem semper priora sunt;
non enim (19) conuertuntur secundum substantiae consequentiam,
ut aquatile quidem (20) cum sit est animal, animal uero cum sit, non necesse est esse (21) aquatile.
Simul ergo natura esse dicuntur quaecumque conuertuntur (22) quidem secundum essentiae consequentiam,
nullo autem modo alterum (23) alteri subsistendi causa est,
et ex eodem genere quae in contrarium (24) sibi diuiduntur;
simpliciter autem simul sunt quorum generatio in (25) eodem tempore est.
Each of these also, the terrestrial, the winged, and the water species, can be divided again into subspecies.
Those species, then, also will be ’simultaneous’ point of nature, which, belonging to the same genus, are distinguished each from each by one and the same method of differentiation.
But genera are prior to species,
for the sequence of their being cannot be reversed.
If there is the species ’water-animal’, there will be the genus ’animal’, but granted the being of the genus ’animal’, it does not follow necessarily that there will be the pecies ’water-animal’.
Those things, therefore, are said to be ’simultaneous’ in nature, the being of each of which involves that of the other,
while at the same time neither is in any way the cause of the other’s being;
those species, also, which are distinguished each from each and opposed within the same genus.
Those things, moreover, are ’simultaneous’ in the unqualified sense of the word which come into being at the same time.
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