He cautiously approached the reptile. The big serpent seemed to be searching in the camp for something to eat. It crawled here and there, poking its ugly head into all the openings visible and overturning several boxes.

“It’s a whopper!” cried Ned as a nearer view showed the real size of the reptile.

Meanwhile the professor was approaching closer and closer, holding the dangling noose ready to slip over the serpent’s head. Suddenly the creature raised itself so that the scientist thought he had a chance. He rushed forward with a cry to the boys to be in readiness. Ned shoved the boat off shore and Jerry stood ready to start the motor, while Bob had secured the end of the rope about a cleat.

All at once the snake caught sight of the man advancing with the rope. It must have been aware of the hostile intentions of the professor for it instantly gave vent to a loud hiss and coiled up ready for action.

“Look out, Mr. Snodgrass!” called Jerry. “He’s got an ugly look!”

The professor did not reply. Stepping cautiously he kept on advancing, holding his noose in readiness. It was a brave act but probably only a person who would dare much in the interests of science would have undertaken it.

Suddenly the professor cast his noose. Now either he was not an expert in the use of the lasso, or the snake instinctively knew how to avoid such dangers. At any rate the reptile swayed its head to one side and the rope fell harmlessly to the ground. The next instant the snake had uncoiled and was wiggling straight for the professor.

“Run!” cried Bob.

“Jump!” advised Jerry.