τὼ .

A. change over: once in Hom., τὼ . . ὁμοιΐον πτολέμοιο πεῖραρ ἐπαλλάξαντες ἐπ’ ἀμφοτέροισι τάνυσσαν crossing, i.e. tying, the rope-end of balanced war, Il. 13.359 (vv.ll. τοί, ἀλλήλοισι, in which case the metaph. is from a tug of war, pulling alternately this way and that); ἐ. ἅλματα ἐμποιοῦντες ἴχνεσιν ἴχνη interchange leaps, i.e. one to leap into the other's steps, X. Cyn. 5.20 (cf. ἐπηλλαγμένα [ἴχνη] 8.3); of καρχαρόδοντα, ἐ. τοὺς ὀδόντας have their teeth fitting in like two saws, Arist. HA 501a18:—Med., [νεῦρα] ἀλλήλοισι ἐπαλλαξάμενα ἐς χιασμὸν σχήματος Aret. SD 1.7:—Pass., cross one another, δόρατα . . ὡς ἥκιστα ἂν ἀλλήλοις ἐπαλλάττοιτο X. Eq.Mag. 3.3; ἐπηλλαγμέναις δῑ ἀλλήλων ταῖς χερσίν with the arms crossed, Plu. Luc. 21; θώρακες ἁλύσεσι λεπταῖς σιδηραῖς ἐπηλλαγμένοι Arr. Tact. 3.5; ποὺς ἐπαλλαχθεὶς ποδί closely joined, E. Heracl. 836: metaph., μή πῃ ὁ λόγος ἐπαλλαχθῇ that it be not entangled, X. Mem. 3.8.1; of permutations and combinations, ‐όμεναι συζυγίας ἀποτελοῦσιν ἐννέα Gal. 6.112.

II. intr., alternate, ὀδόντες ἐπαλλάσσοντες interlocking teeth, Arist. PA 661b18; of leaves, dub. in Thphr. HP 4.6.10.

2. overlap, of classes or species, ib.1.3.2; ἀλλήλοις Arist. GA 733a27; τοῦτο μόνον ἐ. overlaps both classes, ib.774b17; ἡ φώκη ἐ. τῷ γένει τῶν ἰχθύων forms a link with . ., Id. HA 501a22; ταῦτα συνδυαζόμενα ποιεῖ τὰς πολιτείας ἐπαλλάττειν causes them to overlap, Id. Pol. 1317a2; so διὰ τὸ τὴν δύναμιν ἐπαλλάττειν αὐτῶν (sc. two species of τυραννίς)καὶ πρὸς τὴν βασιλείαν ib.1295a9; ὃ ποιεῖ τοὺς λόγους ἐ. makes the arguments confused, ib.1255a13, cf. 1257b35.

b. become confused or intermixed, ἐ. τὰ μόρια Id. GA 769b34; to be interchangeable with, τὰ νοσώδη ἐ. τοῖς βραχυβίοις Id. Long. 464b28.

3. ἐ. τοῦτο τὸ σύμπτωμα τοῖς τοιούτοις this accident invades, makes its way into this class, Id. GA 770b6.