§2.13.113 Καὶ οἱ μὲν ἅνθρωποι καὶ οἱ ὅρυιθες καὶ τὰ ζῳοτόκα καὶ τὰ ᾧοτόκα τῶν τετραπόὅων φυλακὴν ἔχουσι τῆς ὄψεως, τὰ μὲν ζῳοτόκα βλέφαρα δύο, οἷς καὶ σκαρδαμύττουσι, τῶν δʼ ὀρνίθων ἅλλοι τε καὶ οἱ βαρεῖς καὶ τὰ ᾧοτόκα τῶν τετραπόδων τῇ κάτω βλεφαρίδι μύουσιν· σκαρδαμύττουσι δʼ οἱ ὅρυιθες ἐκ τῶν κανθῶν ὑμένι.
13 And humans, birds, viviparous quadrupeds, and oviparous quadrupeds have a protection for their sight; the viviparous having two eyelids, with which they also blink; while of birds, some (especially the heavy ones) and the oviparous quadrupeds close their eyes with the lower eyelid; and birds blink from the corners of their eyes with a membrane.
τοῦ μὲν οὖν φυλακὴν ἔχειν αἴτιον τὸ ὑγρὰ τὰ ὄμματα εἶναι, ἵνα ὄξύ βλέπωσι τοῦτον τὸν τρόπον ὑπὸ τῆς φύσεως.
Now, the cause of their having a protection is that their eyes are moist, so that they may see sharply in this manner by nature.
σκληρόδερμα γὰρ ὄντα ἀβλαβέστερα μὲν ἂν ἦν ὑπὸ τῶν ἔξωθεν προσπιπτόντων, οὐκ ὀξυωπὰ δέ.
For if they were hard-skinned, they would indeed be safer from outward blows, but they would not be sharp-sighted.
§2.13.22 τούτου μὲν οὖν ἕνεκα λεπτὸν τὸ δέρμα τὸ περὶ τὴν κόρην ἐστί, τῆς δὲ σωτηρίας χαέριν τὰ βλέφαραʼ καὶ διὰ τοῦτο σκαρδαμύσσει τε πάντα καὶ μάλιστʼ ἅνθρωπος, πάντα μὲν ὅπως τὰ προσπίπτοντα τοῖς βλεφάροις κωλύωσι (καὶ τοῦτο οὐκ ἐκ προαιρέσεως, ἀλλʼ ἡ φύσις ἐποίησε), πλειστάκις δʼ ὁ ἅνθρωπος διὰ τὸ λεπτοδερμότατος εἷναι.
2 For this reason, then, the skin around the pupil is thin, and for the sake of safety there are eyelids; and because of this, all animals blink, and human beings most of all: all of them in order to prevent things from striking the eyes with their eyelids (and this is not from deliberate choice, but nature has produced it), and human beings most frequently because they have the thinnest skin.
ἡ δὲ βλεφαρίς ἐστι δέρματι περιειλημμένη· διὸ καὶ οὐ συμφύεται οὔτε βλεφαρὶς οὔτʼ ἀκροποσθία, ὅτι ἄνευ σαρκὸς δέρματά ἐστιν.
The eyelid edge is covered with skin; wherefore neither the eyelid nor the prepuce grows together again if cut, because they are skins without flesh.
§2.13.33 τῶν δʼ ἀρνίθεν ὅσοι τῇ 5 κάτω βλεφαρίδι μύουσι, καὶ τὰ ᾧοτόκα τῶν τετραπόδων, διὰ τὴν σκληρότητα τού δέρματος τού περὶ τὴν κεφαλὴν οὕτω μύουσιν.
3 Of birds, those that close their eyes with the lower eyelid, and the oviparous quadrupeds, do so because of the hardness of the skin around the head.
οἱ μὲν γὰρ βαρεῖς τῶν πτερωτῶν διὰ τὸ μὴ πτητικοὶ εἶναι τὴν τῶν πτερῶν αὖξησιν εἰς τὴν τού δέρματος παχύτητα τετραμμένην ἔχουσιν.
For heavy winged creatures, because they are not capable of flight, have the growth of their feathers diverted into the thickness of their skin.
διὸ καὶ οὐτοι μὲν τῷ κάτω βλεφάρῳ μύουσι, περιστεραὶ δὲ καὶ τὰ τοιαύτα ἀμφοῖν.
Therefore, these close their eyes with the lower eyelid, but pigeons and similar birds with both.
§2.13.4τὰ δὲ 4 τετράποδα τῶν ᾠοτόκων φολιδωτά ἐστιν· ταῦτα δὲ σκληρότερα πάντα τριχὸς, ὥστε καὶ τὰ δέρματα τοῦ δέρματος.
4 The oviparous quadrupeds are scaled; and these scales are all harder than hair, so that their skins are also harder than ordinary skin.
τὸ μὲν οὑν περὶ τὴν κεφαλὴν σκληρὸν ἐστιν αὑτοῖς, διόπερ οὐκ ἔχει βλέφαρον ἐκεῖθεν, τὸ δὲ κάτωσθεν σαρκὧδες, ὥστʼ ἔχειν τὸ βλέφαρον λεπτότητα καὶ τάσιν.
Therefore, the part around their head is hard, which is why they do not have an eyelid from that side, but the part below is fleshy, so that the lower eyelid has thinness and tension.
σκαρδαμύττουσι δʼ σἱ βαρεῖς ὄρνιθες τούτῳ μὲν οὕ, τῷ δʼ ὑμέυι, διἀ τὸ βραδεῖαν εἶναι τὴν τούτου κίνησιν, δεῖν δὲ ταχεῖαν γίνεσθαι· ὲ δʼ ὑμὴν τοιούτον.
And heavy birds do not blink with this eyelid but with the membrane, because the movement of the eyelid is slow, whereas it needs to be fast; and the membrane is of such a nature.
§2.13.5ἐκ δὲ τοῦ κανθοῦ τὸν παρὰ 5 τοὺς μυκτὴρας σκαρδαμύττουσιν, ὅτι βέλτιον ἀπʼ ἀρχῆς μιᾶς τὴν φύσιν εἶναι αὐτῶν, ούτοι δʼ ἔχουσιν ἀρχὴν τὴν πρὸς τὸν μυκτὴρα πρόσφυσιν· καὶ τὸ πρόσθιον ἀρχὴ τοῦ πλαγίου μᾶλλον.
5 And they blink from the corner of the eye that is near the nostrils, because it is better for their nature to proceed from a single origin, and they have as their origin the attachment toward the nostril; and the front part is more of an origin than the side part.
τὰ δὲ τετράποδα καὶ ᾧοτόκα οὐ σκαρδαμύττει ὁμοίως, ὅτι οὐδ ʼ ὑγρὰν αὐτοῖς ἀναγκαῖον ἔχειν καὶ ἀκριβὴ τὴν ὄψιν ἐπιγείοις οὗσιν.
But oviparous quadrupeds do not blink in the same way, because, being land animals, they do not need to have a moist and precise sight.
τοῖς δʼ ὄρνισιν ἀναγκαῖον· πόρρῳσθεν γὰρ ἡ χρῆσις τῆς ὄψεως.
But for birds it is necessary, for the use of their sight is from afar.
διὸ καὶ τὰ γαμ ψώνυχα μὲν ὀξυωπά (ἄνωθεν γὰρ αὐτοῖς ἡ θεωρία τῆς τροφῆς, διὸ καὶ ἀναπέτονται ταῦτα μάλιστα τῶν ὀρνέων εἰς ὕψος), τὰ δʼ ἐπίγεια καὶ μὴ πτητικά, οἷον ἀλεκτρυόνες καὶ τὰ τοιαύτα, οὐκ ὀξυωπά· οὐδὲν γὰρ αὐτἀ κατεπείγει πρὸς τὸν βίον.
Therefore, those with crooked talons are sharp-sighted (for they observe their food from above, which is why these birds fly up to the greatest height), whereas those that are ground-dwelling and cannot fly, such as fowls and the like, are not sharp-sighted; for nothing presses them to be so for their livelihood.
§2.13.6οἱ δʼ ἐχθύες καὶ τὰ ἔντομα 6 καὶ τὰ σκληρόδερμα διαφέροντα μὲν ἔχουσι τὰ ὄμματα, βλέφαρον δʼ οὐδὲν οὐτῶν ἔχει.
6 Fish, insects, and crustacea have eyes of different kinds, but none of them has an eyelid.
τὰ μὲν γὰρ σκληρόδερμα ὅλως οὐκ ἔχει· ἡ δὲ τοῦ βλεφάρου χρὴσις ταχεῖαν καὶ δερματικὴν ἔχει τὴν ἐργασίαν·
For the crustacea do not have them at all; and the use of the eyelid requires a rapid and skin-like action.
ἀλλʼ ἀντὶ ταύτης τῆς φυλακῆς πάντα σκληρὸφθαλμά ἐστιν, οἷον βλέποντα διἀ τοῦ βλεφάρου προσπεφυκότος.
Instead of this protection, however, they all have hard eyes, as if they were seeing through an eyelid that has grown onto the eye.
ἐπεὶ δʼ ἀναγκαῖον διὰ τὴν σκληρότητα ἀμβλύτερον βλέπειν, κινουμένους ἐποίησεν ἡ φύσις τοὺς ὀφθαλμοὺς τοῖς ἐντόμοις, καὶ μᾶλλον ἔτι τοῖς σκληροδέρμοις, ὥσπερ ἔνια τῶν τετραπόδων τὰ ὦτα, ὅπως ὀξύτερον βλέπῃ στρέφοντα πρὸς τὸ φῶς καὶ δεχόμενα τὴν αὐγήν.
Since, however, they must necessarily see more dimly because of this hardness, nature made the eyes of insects, and still more those of crustacea, mobile—just as some quadrupeds move their ears—so that they may see more sharply by turning them toward the light and receiving its rays.
§2.13.77 οἱ δʼ ἰχθύες ὑγρόφθαλμοι μέν εἰσιν.
7 Fish, on the other hand, are moist-eyed.
ἀναγκαία γὰρ τοῖς πολλὴν ποιουμένοις κίνησιν ἡ τῆς ὄψεως ἐκ πολλοῦ χρῆσις. τοῖς μὲν σὖν πεζοῖς ὁ ἀὴρ εὐδίοπτος·
For those that move about a great deal, the use of sight from a distance is necessary.
ἐκείνοις δʼ ἐπεὶ τὸ ὕδωρ πρὸς μὲν τὸ ὀξὺ βλέπειν ἐναντίον, οὐκ ἔχει δὲ πολλὰ τὰ προσκρούσματα πρὸς τὴν ὄψιν ὥσπερ ὁ ἀήρ, διὰ μὲν τοῦτʼ οὐκ ἔχει βλέφαρον (οὐδὲν γὰρ ἡ φύσις ποιεῖ μάτην), πρὸς δὲ τὴν παχύτητα τοῦ ὕδατος ὑγρόφθαλμοί εἰσιν.
For while for land animals the air is easy to see through; but for fish, since water is an obstacle to sharp sight, yet does not have many things striking against the eye as the air does, for this reason indeed they have no eyelid (for nature does nothing in vain), but they are moist-eyed to counteract the density of the water.