519 a διὸ καὶ τὸν Ὅμηρόν φασιν ἀντὶ Σκαμάνδρου Ξάνθον προσαγορεύειν αὐτόν.
20Τὰ μὲν οὖν ἄλλα ζῷα οὔτ᾿ ἐντὸς ἔχει τρίχας, τῶν τ᾿ ἀκρωτηρίων ἐν τοῖς πρανέσιν ἀλλ᾿ οὐκ ἐν τοῖς ὑπτίοις· ὁ δὲ δασύπους μόνος καὶ ἐντὸς ἔχει τῶν γνάθων τρίχας καὶ ὑπὸ τοῖς ποσίν. ἔτι δὲ καὶ τὸ μυστακόκητος1 ὀδόντας μὲν ἐν τῷ στόματι οὐκ ἔχει, τρίχας δ᾿ ὁμοίας ὑείαις.
25Αἱ μὲν οὖν τρίχες αὐξάνονται ἀποτμηθεῖσαι κάτωθεν, ἄνωθεν δ᾿ οὔ· τὰ δὲ πτερὰ οὔτ᾿ ἄνωθεν οὔτε κάτωθεν, ἀλλ᾿ ἐκπίπτει. οὐκ ἀναφύεται δ᾿ ἐκτιλθὲν οὔτε τῶν μελιττῶν τὸ πτερὸν οὔθ᾿ ὅσα ἄλλ᾿ ἔχει ἄσχιστον τὸ πτερόν· οὐδὲ τὸ κέντρον, ὅταν ἀποβάλλῃ ἡ μέλιττα, ἀλλ᾿ ἔκτοτε ἀποθνήσκει.2
XIIIΕἰσὶ δὲ καὶ ὑμένες ἐν τοῖς ζῴοις ἅπασι τοῖς ἐναίμοις. 31ὅμοιος δ᾿ ἐστὶν ὁ ὑμὴν δέρματι πυκνῷ καὶ λεπτῷ, ἔστι δὲ τὸ γένος ἕτερον· οὔτε γάρ ἐστι σχιστὸν οὔτε τατόν. περὶ ἕκαστον δὲ τῶν ὀστῶν καὶ περὶ ἕκαστον τῶν σπλάγχνων ὑμήν3 εστι καὶ ἐν τοῖς μείζοσι καὶ ἐν τοῖς ἐλάττοσι ζῴοις· ἀλλ᾿ ἄδηλοι ἐν 519 bτοῖς ἐλάττοσι διὰ τὸ πάμπαν εἶναι λεπτοὶ καὶ μικροί. μέγιστοι δὲ τῶν ὑμένων εἰσὶν οἵ τε περὶ τὸν ἐγκέφαλον δύο, ὧν ὁ περὶ τὸ ὀστοῦν ἰσχυρότερος καὶ παχύτερος τοῦ περὶ τὸν ἐγκέφαλον, ἔπειθ᾿ ὁ περὶ τὴν καρδίαν ὑμήν. διακοπεὶς δ᾿ οὐ συμφύεται
this, they say, is why Homera calls it the Yellow River (Xanthos) instead of Scamander.
All animals except one have no hair internally, and on their extremities the hair appears only on the upper surface, never on the lower. The exception is the hare (or “hairyfoot”): this is the only animal which has hair both inside its mouth and on the underside of its feet. In addition, the moustache-whaleb lacks teeth in its mouth, and has instead hairs similar to pigs’ bristles.
Now hairs that have been cut grow at their base, though not at the tip; whereas feathers do neither, but fall out. A bee’s wing will not grow again if plucked out, nor will the wing of any other creature whose wings are undivided. Nor will a bee’s sting grow again if the bee loses it; from that time the bee begins to die.c
All blooded animals possess membranes. Now a XIII Membranes. membrane resembles a fine close-textured skin; but it differs in character, because it admits neither of division nor of extension. Membrane surrounds every one of the bones and every one of the viscera both in the larger and in the smaller animals, though in the smaller ones they are difficult to detect owing to their excessive fineness and smallness. The largest membranes are those which surround the brain—two of them: the one round the bone is stronger and thicker than the one round the brain itself. Next largest is the membrane round the heart. If cut apart