2. “Let the waters bring forth moving creatures after their kind.” God caused to be born the firstlings of each species to serve as seeds for nature. Their multitudinous numbers are kept up in subsequent succession, when it is necessary for them to grow and multiply. Of another kind is the species of testacea, as muscles, scallops, sea snails, conches, and the infinite variety of oysters. Another kind is that of the crustacea, as crabs and lobsters; another of fish without shells, with soft and tender flesh, like polypi and cuttle fish. And amidst these last what an innumerable variety! There are weevers, lampreys and eels, produced in the mud of rivers and ponds, which more resemble venomous reptiles than fish in their nature. Of another kind is the species of the ovipara; of another, that of the vivipara. Among the latter are sword-fish, cod, in one word, all cartilaginous fish, and even the greater part of the cetacea, as dolphins, seals, which, it is said, if they see their little ones, still quite young, frightened, take them back into their belly to protect them.  8  Narrated by Ælian (Anim i. 16) of the “glaucus,” a fish apparently unknown.

 Let the waters bring forth after their kind . The species of the cetacean is one; another is that of small fish. What infinite variety in the different kinds! All have their own names, different food, different form, shape, and quality of flesh. All present infinite variety, and are divided into innumerable classes. Is there a tunny fisher who can enumerate to us the different varieties of that fish? And yet they tell us that at the sight of great swarms of fish they can almost tell the number of the individual ones which compose it. What man is there of all that have spent their long lives by coasts and shores, who can inform us with exactness of the history of all fish?

Some are known to the fishermen of the Indian ocean, others to the toilers of the Egyptian gulf, others to the islanders, others to the men of Mauretania.  9  Μαυρούσιοι. cf. Strabo, ii. 33. Great and small were all alike created by this first command, by this ineffable power. What a difference in their food! What a variety in the manner in which each species reproduces itself! Most fish do not hatch eggs like birds; they do not build nests; they do not feed their young with toil; it is the water which receives and vivifies the egg dropped into it. With them the reproduction of each species is invariable, and natures are not mixed. There are none of those unions which, on the earth, produce mules and certain birds contrary to the nature of their species. With fish there is no variety which, like the ox and the sheep, is armed with a half-equipment of teeth, none which ruminates except, according to certain writers, the scar.  10  e.g. Arist., De Anim. viii. 2 and Ælian, ii. 54. All have serried and very sharp teeth, for fear their food should escape them if they masticate it for too long a time. In fact, if it were not crushed and swallowed as soon as divided, it would be carried away by the water.

Ἐξαγαγέτω τὰ ὕδατα ἑρπετὰ ψυχῶν ζωσῶν κατὰ γένος. Ἑκάστου γένους τὰς ἀπαρχὰς νῦν, οἱονεὶ σπέρματά τινα τῆς φύσεως, προβληθῆναι κελεύει: τὸ δὲ πλῆθος αὐτῶν ἐν τῇ μετὰ ταῦτα διαδοχῇ ταμιεύεται, ὅταν αὐξάνεσθαι αὐτὰ καὶ πληθύνεσθαι δέῃ. Ἄλλου γένους ἐστὶ τὰ ὀστρακόδερμα προσαγορευόμενα: οἷον κόγχαι, καὶ κτένες, καὶ κοχλίαι θαλάσσιοι, καὶ στρόμβοι, καὶ αἱ μυρίαι τῶν ὀστρέων διαφοραί. Ἄλλο πάλιν παρὰ ταῦτα γένος, τὰ μαλακόστρακα προσειρημένα, κάραβοι, καὶ καρκῖνοι, καὶ τὰ παραπλήσια τούτοις. Ἕτερον παρὰ ταῦτα γένος ἐστὶ τὰ μαλάκια οὕτω προσαγορευθέντα, ὅσων ἡ σὰρξ ἁπαλὴ καὶ χαύνη: πολύποδες, καὶ σηπίαι, καὶ τὰ ὅμοια τούτοις. Καὶ ἐν τούτοις πάλιν διαφοραὶ μυρίαι. Δράκοντες γὰρ καὶ μύραιναι καὶ ἐγχέλυες, αἱ κατὰ τοὺς ἰλυώδεις ποταμοὺς καὶ λίμνας γινόμεναι, τοῖς ἰοβόλοις μᾶλλον τῶν ἑρπετῶν, ἢ τοῖς ἰχθύσι κατὰ τὴν ὁμοιότητα τῆς φύσεως προσεγγίζουσιν. Ἄλλο γένος τὸ τῶν ὠοτοκούντων, καὶ ἄλλο τὸ τῶν ζωοτοκούντων. Ζωοτοκεῖ δὲ τὰ γαλεώδη καὶ οἱ κυνίσκοι, καὶ ἁπαξαπλῶς τὰ σελάχη λεγόμενα. Καὶ τῶν κητῶν τὰ πλεῖστα ζωοτόκα: δελφῖνες, καὶ φῶκαι, ἃ καὶ νεαροὺς ἔτι τοὺς σκύμνους, διαπτοηθέντας ὑπὸ αἰτίας τινὸς, λέγεται πάλιν τῇ γαστρὶ ὑποδεχόμενα περιστέλλειν. Ἐξαγαγέτω τὰ ὕδατα κατὰ γένος. Ἕτερον γένος τὸ κητῶδες, καὶ τὸ τῶν λεπτῶν ἰχθύων ἕτερον. Πάλιν ἐν τοῖς ἰχθύσι μυρίαι διαφοραὶ κατὰ γένη διῃρημέναι: ὧν καὶ ὀνόματα ἴδια, καὶ τροφὴ παρηλλαγμένη, καὶ σχῆμα καὶ μέγεθος καὶ σαρκῶν ποιότητες, πάντα μεγίσταις διαφοραῖς ἀλλήλων κεχωρισμένα, καὶ ἐν ἑτέροις καὶ ἑτέροις εἴδεσι καθεστῶτα. Ποῖοι μὲν οὖν θυννοσκόποι τῶν γενῶν τὰς διαφορὰς ἡμῖν ἀπαριθμήσασθαι δύνανται; Καίτοι φασὶν αὐτοὺς ἐν μεγάλαις ἀγέλαις ἰχθύων καὶ τὸν ἀριθμὸν ἀπαγγέλλειν. Τίς δὲ τῶν περὶ αἰγιαλοὺς καὶ ἀκτὰς καταγηρασάντων δύναται ἡμῖν τὴν ἱστορίαν πάντων δι' ἀκριβείας γνωρίσαι; Ἄλλα γνωρίζουσιν οἱ τὴν Ἰνδικὴν ἁλιεύοντες θάλασσαν: ἄλλα, οἱ τὸν Αἰγύπτιον ἀγρεύοντες κόλπον: ἄλλα, νησιῶται: καὶ ἄλλα, Μαυρούσιοι. Πάντα δὲ ὁμοίως μικρά τε καὶ μεγάλα τὸ πρῶτον ἐκεῖνο πρόσταγμα καὶ ἡ ἄφατος ἐκείνη παρήγαγε δύναμις. Πολλαὶ τῶν βίων αἱ παραλλαγαί: πολλαὶ καὶ αἱ περὶ τὰς διαδοχὰς ἑκάστου γένους διαφοραί. Οὐκ ἐπωάζουσιν οἱ πλεῖστοι τῶν ἰχθύων ὥσπερ αἱ ὄρνιθες, οὔτε καλιὰς πήγνυνται, οὔτε μετὰ πόνων ἐκτρέφουσιν ἑαυτῶν τὰ ἔκγονα: ἀλλὰ τὸ ὕδωρ ὑποδεξάμενον ἐκπεσὸν τὸ ὠὸν, ζῷον ἐποίησεν. Καὶ ἑκάστῳ γένει ἡ διαδοχὴ ἀπαράλλακτος καὶ ἀνεπίμικτος πρὸς ἑτέραν φύσιν. Οὐχ οἷαι τῶν ἡμιόνων ἐπὶ τῆς χέρσου, ἢ καί τινων ὀρνίθων ἐπιπλοκαὶ παραχαρασσόντων τὰ γένη. Οὐδὲν παρὰ τοῖς ἰχθύσιν ἐξ ἡμισείας ὥπλισται τοῖς ὀδοῦσιν, ὡς βοῦς παρ' ἡμῖν καὶ πρόβατον: οὐδὲ γὰρ μηρυκίζει τι παρ' αὐτοῖς, εἰ μὴ τὸν σκάρον μόνον ἱστοροῦσί τινες. Πάντα δὲ ὀξυτάταις ἀκμαῖς ὀδόντων καταπεπύκνωται, ἵνα μὴ τῇ χρονίᾳ μασήσει ἡ τροφὴ διαρρέῃ: ἔμελλε γὰρ, εἰ μὴ ὀξέως κατατεμνομένη τῇ γαστρὶ παρεπέμπετο, ἐν τῇ λεπτοποιήσει διαφορεῖσθαι παρὰ τοῦ ὕδατος.