“Couldn’t tell. There they are again. Look!”

“I see! It is not the man and the girl. It is two men.”

“That is right—or, at least, a man and something that resembles a man.”

“It is Bernard Belmont and his gorilla man!”

“You are right, Merry, my boy; and they, too, are searching for the mouth of the cave. It will be a good scheme to watch them.”

[CHAPTER XVI.—LOST UNDERGROUND.]

The boys followed Belmont and Apollo, being aided in doing so without danger of discovery by the gathering darkness; but they knew very well that, in a short time it would become so dark that they might lose track of the two.

Apollo seemed to be guiding his master to some spot, and they clambered over the rocks with haste that indicated a desire to reach the place without delay.

At last the dwarf paused and swept aside some matted vines from the face of what seemed to be a cliff of solid stone.

A black opening, large enough to admit a man in a stooping posture, was revealed.