There are also marvellous instances to be found of antipathies and sympathies existing between them. The mullet and the wolf-fish[2848] are animated with a mutual hatred; and so too, the conger and the murena gnaw each other’s[2849] tails. The cray-fish has so great a dread of the polypus, that if it sees it near, it expires in an instant: the conger dreads the cray-fish; while, again, the conger tears the body of the polypus. Nigidius informs us that the wolf-fish gnaws the tail of the mullet, and yet that, during certain months, they are on terms of friendship; all those, however, which thus lose their tails, survive their misfortune. On the other hand, in addition to those which we have already mentioned as going in company together, an instance of friendship is found in the balæna and the musculus,[2850] for, as the eye-brows of the former are very heavy, they sometimes fall over its eyes, and quite close them by their ponderousness, upon which the musculus swims before, and points out the shallow places which are likely to prove inconvenient to its vast bulk,[2851] thus serving it in the stead of eyes. We shall now have to speak of the nature of the birds. * * * * * Summary.—Remarkable facts, narratives, and observations, 650. * * * * * Roman authors quoted.—Turranius Gracilis,[2852] Trogus,[2853] Mæcenas,[2854] Alfius Flavus,[2855] Cornelius Nepos,[2856] Laberius the Mimographer,[2857] Fabianus,[2858] Fenestella,[2859] Mucianus,[2860] Ælius Stilo,[2861] Statius Sebosus,[2862] Melissus,[2863] Seneca,[2864] Cicero,[2865] Æmilius Macer,[2866] Messala Corvinus,[2867] Trebius Niger,[2868] Nigidius.[2869] * * * * * Foreign authors quoted.—Aristotle,[2870] King Archelaus,[2871] Callimachus,[2872] Democritus,[2873] Theophrastus,[2874] Thrasyllus,[2874] Hegesidemus,[2875] Cythnius,[2876] Alexander Polyhistor.[2877] BOOK X. THE NATURAL HISTORY OF BIRDS. CHAP. 1. (1.)—THE OSTRICH.