[2231] These works were completed by Nero the successor of Claudius, and consisted of a new and more capacious harbour on the right arm of the Tiber. It was afterwards enlarged and improved by Trajan. This harbour was simply called “Portus Romanus,” or “Portus Augusti;” and around it there sprang up a town known as “Portus,” the inhabitants of which were called “Portuenses.”
[2232] “Naufragiis tergorum.” This may probably mean a shipwreck, in which some hides had fallen into the sea.
[2233] It is remarked by Rezzonico, that Palermus, in the account of this story given by him in B. i. c. 1, has mistaken Pliny’s meaning, and evidently thinks that “unum” refers to the soldiers, and not the boats engaged in the attack.
[2234] “Ora.” Cuvier remarks, that it is not the “mouth of the animal but the nostrils, that are situate on the top of the head, and that through these it sends forth vast columns of water.” Aristotle, in his Hist. Anim. B. i. c. 3, has a similar passage, from which Pliny copied this assertion of his.
[2235] Cuvier remarks, that these are the animals of the cetaceous class, which resemble the quadrupeds in the formation of the viscera, their respiration, and the mammæ; and which, in fact, only differ from them in their general form, which more nearly resembles that of fishes.
[2236] Hist. Anim. B. viii. c. 2.
[2237] “Doctrinæ indaginibus.” This certainly seems a better reading than “doctrina indignis,” which has been adopted by Sillig, and which would make complete nonsense of the passage.
[2238] Dalechamps states that Cælius Rhodiginus, B. iv. c. 15, has entered very fully into this subject.
[2239] Cuvier remarks, on this passage, that the mollusca have, instead of blood, a kind of azure or colourless liquid. He observes also, that insects respire by means of tracheæ, or elastic tubes, which penetrate into every part of the body; and that the gills of fish are as essentially an organ of respiration as the lungs. All, he says, that Pliny adds as to the introduction of air into water, is equally conformable to truth; and that it is by means of the air mingled with the water, or of the atmosphere which they inhale at the surface, that fishes respire.
[2240] In the shape of vapour raised by the action of the sun. In accordance with this opinion, Cicero says, De Nat. Deor. B. ii. s. 27, “The air arises from the respiration of the waters, and must be looked upon as a sort of vapour coming from them.”