It was a familiar scene on this river of the tropics: an alligator lying motionless on the shore, his yellow, mottled jaws open, waiting for his prey. In form and color he seemed a part of the dead branches and tangle of brushwood he had chosen for his resting place. Once recognized, however, and the malignant creature became a vivid symbol of the ruthless death with which he threatened whoever mistook his yawning mouth for a rift in a fallen tree-trunk. "What a monster!" exclaimed David, roused from his daylong dreams. "Estupido!" retorted Miranda. "He wait for his dinner--as you and I--that is all. The so cruel alligator, you know, is good mother for the young ones. She love them better than some womens." "That hideous brute!" "Si, Senor!" declared the doctor. "So soon that they hatch themselves, she carry the young ones in the mouth and teach them to hunt. She fight for them and die, if it be so." Miranda's vague natural history was of the kind derived from wonder-loving natives. It blended well with the Magdalena's scenic marvels, the wild animal life, glimpses of which were caught at every hand, the dark-skinned natives in their rude dugouts--all that set this apart as a sort of primeval world far removed from any hint of the modern. But the skepticism of the scientist was proof against idle tales. "I am not sure that your theory of the alligator is correct, Senor Doctor," remarked Leighton dryly. "Ah, carai!" spluttered Miranda, wheeling about, ever ready for the fray. "What you say about the care of the female alligator for her young may be true enough," said the savant, ignoring the scowl with which he was regarded; "but that the brute over there in the bushes is holding his mouth open by the hour in that ridiculous fashion, hoping that something may walk into it, is unreasonable." "Then, what for she do it?" demanded the doctor severely. "I can't tell you that," admitted Leighton, adding, with a touch of humor, "perhaps he finds it comfortable on a hot day like this to get as much air as he can. Of course, I have no doubt that he would close his mouth quickly enough if any creature walked into it." "I agree with Mr. Leighton," ventured the schoolmaster. "Ah!" sniffed the doctor scornfully. "And you, Senorita?" "Why," said Una doubtfully, enjoying the doctor's wrath, "he certainly does look hungry, doesn't he? I wouldn't trust him--although he seems to be asleep." "And you, Senor?" glaring at David. "Oh, I'm not a naturalist," he laughed. "But, he looks like a pretty good sort of trap, just the same." "Bueno, General, what sayest thou?" asked the doctor somewhat mollified. "What is that cayman doing there under the trees?" General Herran gazed meditatively at the monster who was unconsciously causing this pother in natural history, and his eyes had a reminiscent twinkle as he answered the question: "That cayman with his mouth open is like the Yankee waiting for Colombia to walk in."