But Arlo had no intention whatever of "hie-ing in," being in that sense very much of an "old dog." He barked in response and frisked and wagged his tail, the while keeping well beyond reach of Falkners treacherous grasp. "Rum place this, Glanton," said the latter. "I wonder there ain't any crocs in it." "How do you know there are not?" I said. "Oh hang it, what d'you mean? Why we've swum here often enough, haven't we?" "Not very. Still--it's jolly deep you know. There may be underground tunnels, connecting it with anywhere?" "Oh hang it. I never thought of that. What a chap you are for putting one off a thing, Glanton." "I never said there were, mind. I only suggested the possibility." He raised himself on one elbow, and his then occupation--shying stones at every mud-turtle that showed an unwary head--was suspended. "By Jove! Are there any holes like this round Hensley's place?" he said earnestly. "Not any," I answered. "This one is unique; hence its curiosity." "Because, if there were, that might account for where the old chap's got to. Underground tunnels! I never thought of that, by Jove. What d'you think of that, Edith? Supposing you were having a quiet swim here, and some jolly croc grabbed you by the leg and lugged you into one of those underground tunnels Glanton says there are. Eh?" grinned Falkner, who was fond of teasing his cousins. "I wouldn't be having a quiet swim in it, for one thing. I think it's a horrid place," answered the girl, while I for my part, mildly disclaimed having made any such statement as that which he had attributed to me. "Bosh!" he declared. "Why you can take splendid headers from the middle rock there. Oh--good Lord!" The exclamation was forcible, and to it was appended a sort of amazed gasp from all who saw. And in truth I was not the least amazed of the lot. For there was a disturbance in the depths of the pool. One glimpse of something smooth, and sinuous, and shiny--something huge, and certainly horrible--was all we obtained, as not even breaking the surface to which it rose, the thing, whatever it might be--sank away from sight. "What was it?" "Can't say for certain," I said, replying to the general query. "It didn't come up high enough to take any shape at all. It might have been a big python lying at the bottom of the hole, and concluding it had lain there long enough came up, when the sight of us scared it down again. I'm pretty sure it wasn't a crocodile." "Tell you what, Glanton. You don't catch me taking any more headers in there again in a hurry," said Falkner. "Ugh! If we'd only known!" "There is prestige in the unknown," I said. "It may be something quite harmless--some big lizard, or a harmless snake." "Well it's dashed odd we should just have been talking of that very sort of thing," said the Major. "Let's keep quiet now and watch, and see if it comes up again."