"Megasthenes[161] informs us that in India serpents grow to such an immense size as to swallow stags and bulls; while Metrodorus says that about the river Rhyndacus, in Pontus, they seize and swallow the birds that are flying above them, however high and however rapid their flight. "It is a well-known fact that during the Punic war, at the river Bagrada, a serpent one hundred and twenty feet in length was taken by the Roman army under Regulus, being besieged, like a fortress, by means of balistæ and other engines of war. _Its skin and jaws_ were preserved in a temple at Rome down to the time of the Numantine war. "The serpents, which in Italy are known by the name of boa, render these accounts far from incredible, for they grow to such vast size that a child was found entire in the stomach of one of them which was killed on the Vaticanian Hill during the reign of Emperor Claudius."[162] Aristotle tells us that "in Libya, the serpents, as it has been already remarked, are very large. For some persons say that as they sailed along the coast, they saw the bones of many oxen, and that it was evident to them that they had been devoured by serpents. And, as the ships passed on, the serpents attacked the triremes, and some of them threw themselves upon one of the triremes and overturned it."[163] It is doubtful whether the dragons described by Benjamin of Tudela, who travelled through Europe and the East and returned to Castille in 1173,[164] as infesting the ruins of the palace of Nebuchodonosor at Babylon, so as to render them inaccessible, were creatures of the imagination such as the mediæval mind seems to have loved to dress up, or venomous serpents. But there is little doubt that the so-called dragons of later voyages were simply boas, pythons, or other large serpents, such as those described by John Leo, in his description of a voyage to Africa, as existing in the caverns of Atlas. He says, "There are many monstrous dragons which are thick about the middle, but have slender necks and tails, so that their motion is but slow.[165] They are so venomous, that whatever they bite or touch, certain death ensues." There is also the statement of Job Ludolphus that (in Æthiopia) "the dragons are of the largest size, very voracious, but not venomous."[166] I fancy that at the present day the numbers, magnitude, and terrifying nature of serpents but feebly represent the power which they asserted in the early days of man's existence, or the terror which they then inspired. This subject has been so ably dealt with by a writer of the last century[167] that I feel no hesitation in transcribing his remarks at length.