ing rifles ready and straining their ears for some sound other than
the drumming of rain.

"I don't hear anything," said Roger.

"_Shhh!_" hissed Astro.

They waited, and then from a distance they heard the faint crashing of
underbrush. Gradually it became more distinct until there was no
mistaking its source. A large monster was moving through the jungle near
them!

"What is it?" asked Tom, trying to keep his voice calm.

"A big one," said Astro. "A real big one. And I think it's heading this
way!"

"By the craters of Luna!" gasped Roger. "What do we do?"

"We either run, or stay here and try to blast it."

"Whatever you say, Astro," said Roger. "You're the boss."

"Same here," said Tom. "Call it."

Astro did not answer right away. He strained his ears, listening to the
movements of the advancing monster, trying to ascertain the exact
direction the beast was taking. The noise became more violent, the
crashing more sharply defined as small trees were crushed to the ground.

"If only I knew exactly what it is!" said Astro desperately. "If it's a
tyranno, it walks on its hind legs and has its head way up in the trees,
and could pass within ten feet of us and not see us. But if it's a
bronto, it has a long snakelike neck that he pokes all around and he
wouldn't miss us at a hundred feet!"

"Make up your mind quick, big boy," said Roger. "If that thing gets any
closer, I'm opening up with this blaster. He might eat me, but I'll sure
make his teeth rattle first!"

The ground began to shake as the approaching monster came nearer. Astro
remained still, ears straining for some sound to indicate exactly what
was crashing down on them.

Above them, the shrill scream of an anthropoid suddenly pierced the dark
night as its tree home was sent crashing to the ground. There was a
growing roar and the crashing stopped momentarily.

"Let's get out of here," said Astro tensely. "That's a tyranno, but he's
down on all fours now, looking for that monkey! Keep together and make
as little noise as you can. No talking. Keep your blasters and emergency
lights ready. If he discovers us, you shine the light on his face Roger,
and Tom and I will shoot. O.K.?"

Tom and Roger agreed.

"All right," said Astro, "let's go--and spaceman's luck!"

CHAPTER 7

"What can I do for you, Officer?"

Connel heaved his bulk out of the jet launch and looked hard at the man
standing in front of him. "You Rex Sinclair?"

Sinclair