ἄναγε -- εἰς τοὐπίσω: ‘fall back then’: cf. Ar. 383 ἄναγ᾽ ἐπὶ σκέλος, with Blaydes' note. The metaphor is not naval (as Ast and Stallbaum hold), but military, nor is ἀνάγειν (ναῦν) even in naval language ‘inhibere,’ but ‘put out to sea,’ as in Hdt. VII 100, VIII 76 et al. and occasionally in Attic (for ἀνάγεσθαι). Cf. ἀνεχώρησας 528 D.

οὐκ ὀρθῶς: see on τὸ ἐχόμενον τούτου 526 C. The subjects ought to follow each other in the order of their complexity: see App. II. Plato's error was of course deliberately “contrived to emphasize the principle which it violated” (Bosanquet), and also, it may be added, to enable him to call especial attention to the study of Stereometry, on which he laid very great stress (527 D note).

ἤδη should be taken with ὄν (‘already in revolution’), not (as D. and V.) with λαβόντες.