§77 ἑκάστην τῶν ἐν τοῖς ῥηθεῖσι μέρεσιν ἀρχῶν, δῆλον οὖν ὡς ἢ μόνοις ἢ μάλιστα τούτοις ὑπάρχει τῶν ζῴων ἡ κατὰ τόπον κίνησις, ἃ δυσὶν ἢ τέτταρσι ποιεῖται σημείοις τὴν κατὰ τόπον μεταβολήν.
7 each of the principles in the mentioned parts. It is clear, then, that local movement belongs either only or most of all to those animals which make their local change by means of two or four points.
ὥστʼ ἐπεὶ σχεδὸν τοῖς ἐναίμοις τοῦτο μάλιστα συμβέβηκε, φανερὸν ὅτι πλείοσί τε σημείοις τεττάρων οὐθὲν οἷόν τε κινεῖσθαι τῶν ἐναίμων ζῴων, καὶ εἴ τι τέτταρσι σημείοις κινεῖσθαι πέφυκε μόνον, ἀναγκαῖον τοῦτʼ εἶναι ἔναιμον.
So that, since this is especially the case with blooded animals, it is manifest that no blooded animal can move by more than four points, and if anything is of a nature to move by four points only, it must of necessity be blooded.
ὁμολογεῖ δὲ τοῖς λεχθεῖσι καὶ τὰ συμβαίνοντα περὶ τὰ ζῷα.
And what happens concerning animals agrees with what has been said.
τῶν μὲν γὰρ ἐναίμων οὐδὲν εἰς πλείω διαιρούμενον δύναται ζῆν οὐθένα χρόνον ὡς εἰπεῖν, τῆς τε κατὰ τόπον κινήσεως, καθʼ ἣν ἐκινεῖτο συνεχὲς ὂν καὶ μὴ διῃρημένον, οὐ δύναται κοινωνεῖν· τῶν δʼ ἀναίμων τε καὶ πολυπόδων ἔνια διαιρούμενα δύναται ζῆν πολὺν χρόνον ἑκάστῳ τῶν μερῶν, καὶ κινεῖσθαι τὴν αὐτὴν ἥνπερ καὶ πρὶν διαιρεθῆναι κίνησιν, οἷον αἵ τε καλούμεναι σκολόπενδραι καὶ ἄλλα τῶν ἐντόμων καὶ προμήκων· πάντων γὰρ τούτων καὶ τὸ ὄπισθεν μέρος ἐπὶ τὸ αὐτὸ πσιεῖται τὴν πορείαν τῷ ἔμπροσθεν.
For of blooded animals none, when divided into several parts, is able to live for any length of time, so to speak, nor can they share in that local movement in which they moved while they were continuous and undivided; but of bloodless and polypod animals, some when divided can live for a long time in each of their parts, and can move with the same movement as before being divided, as for example the so-called centipedes and other insects and elongated animals; for in all of these, even the back part makes its progress in the same direction as the front.
αἴτιον δὲ τοῦ διαιρούμενα ζῆν ὅτι, καθάπερ ἂν εἴ τι συνεχὲς ἐκ πολλῶν εἴη ζῴων συγκείμενον, οὕτως ἕκαστον αὐτῶν συνέστηκε.
The cause of their living when divided is that each of them is constituted just as if it were a continuous thing composed of many animals.
φανερὸν δὲ τοῦτο ἐκ τῶν πρότερον εἰρημένων, διότι τοῦτον ἔχει τὸν τρόπον.
And this is clear from what has been said before, namely, why it is in this way.
δυσὶ γὰρ ἢ τέτταρσι κινεῖσθαι πέφυκε σημείοις τὰ μάλιστα συνεστηκότα κατὰ φύσιν, ὁμοίως δὲ καὶ τῶν ἐναίμων ὅσα ἄποδά ἐστι.
For those that are best constituted according to nature are of a nature to move by two or four points, and likewise also those of the blooded animals that are footless.
καὶ γὰρ ταῦτα κινεῖται τέτταρσι σημείοις, διʼ ὧν τὴν κίνησιν ποιεῖται. δυσὶ γὰρ χρώμενα προέρχεται καμπαῖς· τὸ γὰρ δεξιὸν καὶ ἀριστερὸν τὸ πρόσθιον καὶ ὀπίσθιον ἐν τῷ πλάτει ἐστὶν ἐν ἑκατέρᾳ τῇ καμπῇ αὐτοῖς, ἐν μὲν τῷ πρὸς τὴν κεφαλὴν μέρει τὸ πρόσθιον σημεῖον δεξιόν τε καὶ ἀριστερόν, ἐν δὲ τῷ πρὸς τὴν οὐρὰν τὰ ὀπίσθια σημεῖα.
For these also move by four points, through which they make their movement; for they proceed by using two undulations; for the right and left, the front and back, are in their width in each of their undulations; namely, in the part toward the head is the front point, right and left, and in the part toward the tail are the back points.
δοκεῖ δὲ δυοῖν σημείοιν κινεῖσθαι, τῇ τʼ ἔμπροσθεν ἁφῇ καὶ τῇ ὕστερον.
And they seem to move by two points, by the contact in front and that behind.
αἴτιον δʼ ὅτι στενὸν κατὰ πλάτος ἐστίν, ἐπεὶ καὶ ἐν τούτοις τὸ δεξιὸν ἡγεῖται, καὶ ἀνταποδίδωσι κατὰ τὸ ὄπισθεν, ὥσπερ ἐν τοῖς τετράποσι.
The cause of this is that they are narrow in width, since even in these the right side leads, and there is a corresponding response in the back, just as in quadrupeds.
τῶν δὲ κάμψεων αἴτιον τὸ μῆκος· ὥσπερ γὰρ οἱ μακροὶ τῶν ἀνθρώπων λορδοὶ βαδίζουσι, καὶ τοῦ δεξιοῦ ὤμου εἰς τὸ πρόσθεν ἡγουμένου (τὸ γὰρ ἀριστερὸν ἰσχίον εἰς | τοὔπισθεν μᾶλλον ἀποκλίνει, καὶ τὸ μέσον κοῖλον γίνεται καὶ λορδόν) οὕτω δεῖ νοεῖν καὶ τοὺς ὄφεις κινουμένους ἐπὶ τῇ γῇ λορδούς.
And the cause of the undulations is their length; for just as tall men walk with their backs bent, with the right shoulder leading forward (for the left hip inclines more to the rear, and the middle becomes hollow and swayed), so one must conceive of snakes moving on the ground with swayed bodies.
σημεῖον δʼ ὅτι ὁμοίως κινοῦνται τοῖς τετράποσιν· ἐν μέρει γὰρ μεταβάλλουσι τὸ κοῖλον καὶ τὸ κυρτόν.
And the sign that they move similarly to quadrupeds is that they alternate the hollow and the convex parts.
ὅταν γὰρ τὸ ἀριστερὸν πάλιν τῶν προσθίων ἡγήσηται, ἐξ ἐναντίας πάλιν τὸ κοῖλον γίνεται· τὸ γὰρ δεξιὸν ἐντὸς πάλιν γίνεται.
For when the left of the front parts leads in turn, the hollow occurs on the opposite side again; for the right becomes inside again.
σημεῖον δεξιὸν πρόσθιον ἐφʼ οὗ Α, ἀριστερὸν ἐφʼ οὗ Β, ὀπίσθιον ἀριστερὸν ἐφʼ οὗ Γ. δεξιὸν ἐφʼ οὗ ∠.
Let the right front point be A, the left B, the left back Γ, and the right [back] ∠.
οὕτω δὲ κινοῦνται τῶν μὲν χερσαίων οἱ ὄφεις, τῶν δʼ ἐνύδρων αἱ ἐγχέλεις καὶ οἱ γόγγροι καὶ αἱ μύρσιναι, καὶ τῶν ἄλλων ὅσα ἔχει τὴν μορφὴν ὀφιωδεστέραν.
In this way move, among land animals, snakes, and among water animals, eels, congers, and morays, and all others that have a more snake-like form.
πλὴν ἔνια μὲν τῶν ἐνύδρων τῶν τοιούτων οὐδὲν ἔχει πτερύγιον, οἷον αἱ μύραιναι, ἀλλὰ χρῆται τῇ θαλάττῃ ὥσπερ οἱ ὄφεις τῇ γῇ καὶ τῇ θαλάττῃ (νέουσι γὰρ οἱ ὄφεις ὁμοίως καὶ ὅταν κινῶνται ἐπὶ τῆς γῆς) τὰ δὲ δύʼ ἔχει πτερύγια μόνον, οἷον οἵ τε γόγγροι καὶ αἱ ἐγχέλυες καὶ γένος τι κεστρέων, ο γίνονται ἐν τῇ λίμνῃ τῇ ἐν Σιφαῖς.
Except that some of such water animals have no fin at all, like morays, but use the sea just as snakes use the earth and the sea (for snakes swim in a similar way to when they move on the earth); while others have only two fins, like congers, eels, and a certain kind of grey mullet which are found in the lake at Siphae.
καὶ διὰ τοῦτο ταῖς καμπαῖς ἐλάττοσι κινοῦνται ἐν τῷ ὑγρῷ ἢ ἐν τῇ γῇ τὰ ζῆν εἰωθότα ἐν τῇ γῇ, καθάπερ τὸ τῶν ἐγχελύων γένος.
And for this reason, those accustomed to live on land move with fewer undulations in water than on land, just as the class of eels does.
οἱ δὲ δύο πτερύγια ἔχοντες τῶν κεστρέων τῇ καμπῇ ἀνισάζουσιν ἐν τῷ ὑγρῷ τὰ τέτταρα σημεῖα.
And those of the grey mullets that have two fins compensate for the four points in water by means of their undulation.