The North, too, produces herds of wild horses, as Africa and Asia do of wild asses;[1655] there is, also, the elk, which strongly resembles our steers, except that it is distinguished by the length of the ears and of the neck. There is also the achlis,[1656] which is produced in the island of Scandinavia;[1657] it has never been seen in this city, although we have had descriptions of it from many persons; it is not unlike the elk, but has no joints in the hind leg. Hence, it never lies down, but reclines against a tree while it sleeps; it can only be taken by previously cutting into the tree, and thus laying a trap for it, as otherwise, it would escape through its swiftness. Its upper lip is so extremely large, for which reason it is obliged to go backwards when grazing; otherwise, by moving onwards, the lip would get doubled up. In Pæonia, it is said, there is a wild animal known as the bonasus;[1658] it has the mane of the horse, but is, in other respects, like the bull, with horns, however, so much bent inwards upon each other, as to be of no use for the purposes of combat. It has therefore to depend upon its flight, and, while in the act of flying, it sends forth its excrements, sometimes to a distance of even three jugera;[1659] the contact of which burns those who pursue the animal, just like a kind of fire. CHAP. 17.—LIONS; HOW THEY ARE PRODUCED. It is a remarkable fact, that pards,[1660] panthers, lions, and other animals of this kind, walk with the points of their nails concealed in a sheath in the body, lest they should be broken or blunted; and that, when they run, their hooked claws are turned backwards, and are never extended, except in the act of seizing their prey.[1661]