§2.13Τῶν δ’ ἐνύδρων ζῴων τὸ τῶν ἰχθύων γένος ἓν ἀπὸ τῶν ἄλλων ἀφώρισται, πολλὰς περιέχον ἰδέας.
Among aquatic animals, the class of fishes is set apart as a single group from the others, containing many forms.
Κεφαλὴν μὲν γὰρ ἔχει καὶ τὰ πρανῆ καὶ τὰ ὕπτια, ἐν ᾧ τόπῳ ἡ γαστὴρ καὶ τὰ σπλάγχνα· καὶ ὀπίσθιον οὐραῖον συνεχὲς ἔχει καὶ ἄσχιστον·
For it has a head, a back, and under parts, in which region are the stomach and the viscera; and it has a continuous, undivided tail part at the rear, though this is not similar in all.
τοῦτο δ’ οὐ πᾶσιν ὅμοιον. Αὐχένα δ’ οὐδεὶς ἔχει ἰχθύς, οὐδὲ κῶλον οὐθέν, οὐδ’ ὄρχεις ὅλως, οὔτ’ ἐντὸς οὔτ’ ἐκτός, οὐδὲ μαστούς.
No fish, however, has a neck, nor any limb, nor testicles at all, either internal or external, nor breasts.
Τοῦτο μὲν οὖν ὅλως οὐδ’ ἄλλο οὐθὲν τῶν μὴ ζῳοτοκούντων, οὐδὲ τὰ ζῳοτοκοῦντα πάντα, ἀλλ’ ὅσα εὐθὺς ἐν αὑτοῖς ζῳοτοκεῖ καὶ μὴ ᾠοτοκεῖ πρῶτον.
Indeed, this latter feature is not possessed by any of the non-viviparous animals at all, nor even by all of the viviparous ones, but only by those that are directly viviparous within themselves and do not first produce eggs.
Καὶ γὰρ ὁ δελφὶς ζῳοτοκεῖ, διὸ ἔχει μαστοὺς δύο, οὐκ ἄνω δ’ ἀλλὰ πλησίον τῶν ἄρθρων.
For indeed the dolphin is viviparous, which is why it has two breasts, not on the upper part of the body but near the joints.
Ἔχει δ’ οὐχ ὥσπερ τὰ τετράποδα ἐπιφανεῖς θηλάς, ἀλλ’ οἷον ῥύακας δύο, ἑκατέρωθεν ἐκ τῶν πλαγίων ἕνα, ἐξ ὧν τὸ γάλα ῥεῖ· καὶ θηλάζεται ὑπὸ τῶν τέκνων παρακολουθούντων· καὶ τοῦτο ὦπται ἤδη ὑπό τινων φανερῶς.
It does not have visible nipples like quadrupeds, but rather two channels, one on each side, from which the milk flows; and it is suckled by its young as they follow alongside; and this has already been clearly observed by some.
Οἱ δ’ ἰχθύες, ὥσπερ εἴρηται, οὔτε μαστοὺς ἔχουσιν οὔτε αἰδοίων πόρον ἐκτὸς οὐθένα φανερόν.
Fishes, on the other hand, as has been said, have neither breasts nor any visible external genital passage.
Ἴδιον δ’ ἔχουσι τό τε τῶν βραγχίων, ᾗ τὸ ὕδωρ ἀφιᾶσι δεξάμενοι κατὰ τὸ στόμα, καὶ τὰ πτερύγια, οἱ μὲν πλεῖστοι τέτταρα, οἱ δὲ προμήκεις δύο, οἷον ἐγχέλυς, ὄντα πρὸς τὰ βράγχια.
They have, as a unique feature, gills, through which they discharge the water they have taken in through the mouth, and fins, most having four, but the elongated ones having two, such as the eel, situated near the gills.
Ὁμοίως δὲ καὶ κεστρεῖς, οἷον ἐν Σιφαῖς οἱ ἐν τῇ λίμνῃ, δύο, καὶ ἡ καλουμένη ταινία ὡσαύτως.
Likewise, grey mullets, such as those in the lake at Siphae, have two, and the so-called ribbon-fish in like manner.
Ἔνια δὲ τῶν προμήκων οὐδὲ πτερύγια ἔχει, οἷον σμύραινα, οὐδὲ τὰ βράγχια διηρθρωμένα ὁμοίως τοῖς ἄλλοις ἰχθύσιν.
Some of the elongated ones do not even have fins, such as the moray eel, nor are their gills articulated in the same way as in other fishes.
Αὐτῶν δὲ τῶν ἐχόντων βράγχια τὰ μὲν ἔχει ἐπικαλύμματα τοῖς βραγχίοις, τὰ δὲ σελάχη πάντα ἀκάλυπτα.
Among those that have gills, some have opercula, while the cartilaginous fishes are all uncovered.
Καὶ τὰ μὲν ἔχοντα καλύμματα πάντα ἐκ πλαγίου ἔχει τὰ βράγχια, τῶν δὲ σελαχῶν τὰ μὲν πλατέα κάτω ἐν τοῖς ὑπτίοις, οἷον νάρκη καὶ βάτος, τὰ δὲ προμήκη ἐν τοῖς πλαγίοις, οἷον πάντα τὰ γαλεώδη.
And those with covers all have their gills on the sides, whereas among the cartilaginous fishes, the flat ones have them below on their under parts, such as the torpedo and the ray, while the elongated ones have them on the sides, such as all the dogfish.
Ὁ δὲ βάτραχος ἐκ πλαγίου μὲν ἔχει, καλυπτόμενα δ’ οὐκ ἀκανθώδει καλύμματι ὥσπερ οἱ μὴ σελαχώδεις, ἀλλὰ δερματώδει.
The angler-fish has them on the sides, covered not by a thorny cover like the non-cartilaginous fishes, but by a skin-like one.
Ἔτι δὲ τῶν ἐχόντων βράγχια τῶν μὲν ἁπλᾶ ἐστὶ τὰ βράγχια, τῶν δὲ διπλᾶ· τὸ δ’ ἔσχατον πρὸς τὸ σῶμα πάντων ἁπλοῦν.
Furthermore, of those having gills, some have single gills, while others have double ones; but the one closest to the body is single in all of them.
Καὶ πάλιν τὰ μὲν ὀλίγα βράγχια ἔχει, τὰ δὲ πλῆθος βραγχίων· ἴσα δ’ ἐφ’ ἑκάτερα πάντες.
Again, some have few gills, and others a large number of gills; but they are equal on each side in all.
Ἔχει δ’ ὁ ἐλάχιστα ἔχων ἓν ἐφ’ ἑκάτερα βράγχιον, διπλοῦν δὲ τοῦτο, οἷον κάπρος· οἱ δὲ δύο ἐφ’ ἑκάτερα, τὸ μὲν ἁπλοῦν τὸ δὲ διπλοῦν, οἷον γόγγρος καὶ σκάρος· οἱ δὲ τέτταρα ἐφ’ ἑκάτερα ἁπλᾶ, οἷον ἔλλοψ, συναγρίς, σμύραινα, ἐγχέλυς· οἱ δὲ τέτταρα μὲν δίστοιχα δὲ πλὴν τοῦ ἐσχάτου, οἷον κίχλη καὶ πέρκη καὶ γλάνις καὶ κυπρῖνος.
The one with the fewest has one gill on each side, and this is double, such as the boar-fish; some have two on each side, one single and one double, such as the conger eel and the parrot-fish; others have four single ones on each side, such as the elops, the dentex, the moray eel, and the eel; and others have four, but in double rows except for the last one, such as the wrasse, the perch, the sheat-fish, and the carp.
Ἔχουσι δὲ καὶ οἱ γαλεώδεις διπλᾶ πάντες, καὶ πέντ’ ἐφ’ ἑκάτερα· ὁ δὲ ξιφίας ὀκτὼ διπλᾶ.
The dogfish also all have double ones, and five on each side; while the swordfish has eight double ones.
Περὶ μὲν οὖν πλήθους βραγχίων ἐν τοῖς ἰχθύσι τοῦτον ἔχει τὸν τρόπον.
Regarding the number of gills in fishes, then, this is how it stands.
Ἔτι δὲ πρὸς τἆλλα ζῷα οἱ ἰχθύες διαφέρουσι πρὸς τῇ διαφορᾷ τῇ περὶ τὰ βράγχια· οὔτε γὰρ ὥσπερ τῶν πεζῶν ὅσα ζῳοτόκα ἔχει τρίχας, οὔθ’ ὥσπερ ἔνια τῶν ᾠοτοκούντων τετραπόδων φολίδας, οὔθ’ ὡς τὸ τῶν ὀρνέων γένος πτερωτόν, ἀλλ’ οἱ μὲν πλεῖστοι αὐτῶν λεπιδωτοί εἰσιν, ὀλίγοι δέ τινες τραχεῖς, ἐλάχιστον δ’ ἐστὶ πλῆθος αὐτῶν τὸ λεῖον.
Furthermore, compared to other animals, fishes differ in addition to the difference regarding the gills; for they do not have hair like those of the terrestrial animals that are viviparous, nor scales like some of the egg-laying quadrupeds, nor are they feathered like the class of birds, but most of them are scaly, a few are rough, and the smallest number of them is smooth.
Τῶν μὲν οὖν σελαχῶν τὰ μὲν τραχέα ἐστὶ τὰ δὲ λεῖα, γόγγροι δὲ καὶ ἐγχέλυες καὶ θύννοι τῶν λείων.
Among the cartilaginous fishes, indeed, some are rough and others smooth, and congers, eels, and tunnies are among the smooth ones.
Καρχαρόδοντες δὲ πάντες οἱ ἰχθύες ἔξω τοῦ σκάρου· καὶ πάντες ἔχουσιν ὀξεῖς τοὺς ὀδόντας καὶ πολυστοίχους, καὶ ἔνιοι ἐν τῇ γλώττῃ.
All fishes have jagged teeth except the parrot-fish; and all have sharp teeth in many rows, and some even on the tongue.
Καὶ γλῶτταν σκληρὰν καὶ ἀκανθώδη ἔχουσι, καὶ προσπεφυκυῖαν οὕτως ὥστ’ ἐνίοτε μὴ δοκεῖν ἔχειν.
They also have a hard and thorny tongue, so attached that sometimes they seem not to have one.
Τὸ δὲ στόμα οἱ μὲν ἀνερρωγός, ὥσπερ ἔνια τῶν ζῳοτόκων καὶ τετραπόδων.
As for the mouth, some have it wide open, like some of the viviparous quadrupeds.
Τῶν δ’ αἰσθητηρίων τῶν μὲν ἄλλων οὐθὲν ἔχουσι φανερὸν οὔτ’ αὐτὸ οὔτε τοὺς πόρους, οὔτ’ ἀκοῆς οὔτ’ ὀσφρήσεως· ὀφθαλμοὺς δὲ πάντες ἔχουσιν ἄνευ βλεφάρων, οὐ σκληρόφθαλμοι ὄντες.
Of the sense organs, they have no other visible organ itself nor its passages, neither of hearing nor of smell; but all have eyes without eyelids, though they are not hard-eyed.
Ἔναιμον μὲν οὖν ἐστὶν ἅπαν τὸ τῶν ἰχθύων γένος, εἰσὶ δ’ αὐτῶν οἱ μὲν ᾠοτόκοι οἱ δὲ ζῳοτόκοι, οἱ μὲν λεπιδωτοὶ πάντες ᾠοτόκοι, τὰ δὲ σελάχη πάντα ζῳοτόκα πλὴν βατράχου.
Thus, the entire class of fishes is red-blooded, and some of them are oviparous and others viviparous; all those with thin scales are oviparous, while all the cartilaginous ones are viviparous except for the angler-fish.