A reply to his admonition came from another quarter, for almost in front of the swimmers rose a huge black object, quickly followed by another. In the semi-light the two men could see that these were enormous hippopotami, distinguish even their thick lips and wire-like bristles, and hear the business-like snap of their formidable teeth, capable of biting the side of a boat and shaking the craft like a terrier does a rat. The two amphibians were gambolling. So intent were they that the swimmers were unnoticed, but for half a minute after the hippos had passed Denbigh and O'Hara floated motionless, not trusting to swim forward another foot. At length, after a seemingly interminable space of time, the mangrove-covered shore loomed up against the moonlit sky. The banks, thrown into deep shadow, were invisible, until O'Hara, who was now leading, felt his foot touch the slimy ooze that fringed the shore. With feelings of relief the Irishman waded to the bank and awaited Denbigh's emergence from the river. "Thank God," he muttered fervently as Denbigh joined him. "Now, what's the move?" "Dress," replied his chum laconically. The two men unfastened their bundles, and proceeded to sacrifice one of their scanty stock of handkerchiefs as a towel. To allow the foetid fresh water to dry on them would be courting a speedy attack of black-water fever. "We can't see the _Myra_," whispered O'Hara. "How shall we know where to 'kick-off' when we return?" "Bend that damp handkerchief on to one of the bushes," replied Denbigh. "We'll have to take jolly good care to----" His words ended abruptly, and he found himself sitting on the soft ground. In order to facilitate the dressing performance he had sat down upon what he imagined to be a log. The "log" promptly lurched forward and overthrew him. It was a healthy specimen of a crocodile. [Illustration: THE "LOG" WAS A HEALTHY SPECIMEN OF A CROCODILE] O'Hara gripped his chum's hand and literally lifted him to his feet. Both men took to their heels, with the now aroused saurian in pursuit. Luckily the animal was not quick at turning, and before it could do so the two subs placed a safe distance between them and their pursuer. "There may be others," gasped Denbigh, who half-dressed was clutching the rest of his clothing. "The river bank is too jolly risky. I had my doubts about it. We'll cut inland and risk the forest. It's high ground, as far as I could judge when we came up stream. Therefore it ought not to be swampy. What's more, we'll save half the distance." "And, possibly, take double the time," added O'Hara, who, although willing to risk the unknown perils of the mangrove forest to the partly-known adversities of the river banks, was rather doubtful as to his comrade's skill in navigation on dry land.