They looked on all sides, but saw nothing.

Again, far away, they heard another yell, and they ran out again into the passage.
This narrow entry, as the investigating Ralph had already discovered, continued for a dozen yards past the doorway which led to the chambers, but there it ended in a rocky wall about five feet high.

Above this was an aperture extending to the roof of the passage, but Ralph, having a wholesome fear of snakes, had not cared to climb over the wall to see what was beyond.
When the captain and Ralph had reached the end of the passage, they heard another cry, and there could be no doubt that it came through the aperture by which they stood.

Instantly Ralph scrambled to the top of the wall, pushed himself head foremost through the opening, and came down on the other side, partly on his hands and partly on his feet.

Had the captain been first, he would not have made such a rash leap, but now he did not hesitate a second.