〃You snap off the tip and screw on a needle；〃 Muldoon explained。
Gennaro found a plastic package of large needles； each the diameter of his fingertip。 He screwed one onto the canister。 The opposite end of the canister had a circular lead weight。
〃That's the plunger。 presses on impact。〃 Muldoon sat forward with the air rifle across his knees。 It was made of heavy gray tubular metal and looked to Gennaro like a bazooka or a rocket launcher。
〃What's MORO…709？〃
〃Standard animal trank；〃 Muldoon said； 〃Zoos around the world use it。 We'll try a thousand cc's to start。〃 Muldoon cracked open the chamber； which was large enough to insert his fist。 He slipped the canister into the chamber and closed it。
〃That should do it；〃 Muldoon said。 〃Standard elephant gets about two hundred cc's； but they're only two or three tons each。 Tyrannosaurus rex is eight tons； and a lot meaner。 That matters to the dose。〃
〃Why？〃
〃Animal dose is partly body weight and partly temperament。 You shoot the same dose of 709 into an elephant； a hippo； and a rhino…you'll immobilize the elephant； so it just stands there like a statue。 You'll slow down the hippo； so it gets kind of sleepy but it keeps moving。 And the rhino will just get fighting mad。 But； on the other hand； you chase a rhino for more than five minutes in a car and he'll drop dead from adrenaline shock。 Strange bination of tough and delicate。〃
Muldoon drove slowly toward the river； moving closer to the tyrannosaur。 〃But those are all mammals。 We know a lot about handling mammals； because zoos are built around the big mammalian attractions…lions； tigers； bears； elephants。 We know a lot less about reptiles。 And nobody knows anything about dinosaurs。 The dinosaurs are new animals。〃
〃You consider them reptiles？〃 Gennaro said。
〃No；〃 Muldoon said； shifting gears。 〃Dinosaurs don't fit existing categories。〃 He swerved to avoid a rock。 〃Actually； what we find is； the dinosaurs were as variable as mammals are today。 Some dinos are tame and cute； and some are mean and nasty。 Some of them see well； and some of them don't。 Some of them are stupid； and some of them are very； very intelligent。〃
〃Like the raptors？〃 Gennaro said。
Muldoon nodded。 〃Raptors are smart； Very smart。 Believe me； all the problems we have so far；〃 he said； 〃are nothing pared with what we'd have if the raptors ever got out of their holding pen。 Ah。 I think this is as close as we can get to our Rexy。〃
Up ahead； the tyrannosaur was poking its head through the branches； peering toward the river。 Trying to get through。 Then the animal moved a few yards downstream； to try again；
〃Wonder what he sees in there？〃 Gennaro said。
〃Hard to know；〃 Muldoon said。 〃Maybe he's trying to get to the microceratopsians that scramble around in the branches。 They'll run him a merry chase。〃
Muldoon stopped the Jeep about fifty yards away from the tyrannosaur； and turned the vehicle around。 He left the motor running。 〃Get behind the wheel；〃 Muldoon said。 〃And put your seat belt on。〃 He took another canister and booked it onto his shirt。 Then he got out。
Gennaro slid behind the wheel。 〃You done this very often before？〃
Muldoon belched。 〃Never。 I'll try to get him just behind the auditory meatus。 We'll see how it goes from there。〃 He walked ten yards behind the Jeep and crouched down in the grass on one knee。 He steadied the big gun against his shoulder； and flipped up the thick telescopic sight。 Muldoon aimed at the tyrannosaur； which still ignored them。
There was a burst of pale gas； and Gennaro saw a white streak shoot forward in the air toward the tyrannosaur。 But nothing seemed to happen。
Then the tyrannosaur turned slowly； curiously； to peer at them。 It moved its head from side to side； as if looking at them with alternate eyes。
Muldoon had taken down the launcher； and was loading the second canister。
〃You hit him？〃 Gennaro said。
Muldoon shook his head。 〃Missed。 Damn laser sights 。 。 。 See if there's a battery in the case。〃
〃A what？〃 Gennaro said。
〃A battery；〃 Muldoon said。 〃It's about as big as your finger。 Gray markings。〃
Gennaro bent over to look in the steel case。 He felt the vibration of the Jeep； heard the motor ticking over。 He didn't see a battery。 The tyrannosaur roared。 To Gennaro it was a terrifying sound； rumbling from the great chest cavity of the animal； bellowing out over the landscape。 He sat up sharply and reached for the steering wheel； put his hand on the gearshift。 On the radio； he heard a voice say； 〃Muldoon。 This is Arnold。 Get out of there。 Over。〃
〃I know what I'm doing；〃 Muldoon said。
The tyrannosaur charged。
Muldoon stood his ground。 Despite the creature racing toward him； he slowly and methodically raised his launcher； aimed； and fired。 Once again； Gennaro saw the puff of smoke； and the white streak of the canister going toward the animal。
Nothing happened。 The tyrannosaur continued to charge。
Now Muldoon was on his feet and running； shouting； 〃Go！ Go！〃 Gennaro put the Jeep in gear and Muldoon threw himself onto the side door as the Jeep lurched forward。 The tyrannosaur was closing rapidly； and Muldoon swung the door open and climbed inside。
〃Go； damn it！ Go！〃
Gennaro floored it。 The Jeep bounced precariously； the front end nosing so high they saw only sky through the windshield； then slamming down again toward the ground and racing forward again。 Gennaro headed for a stand of trees to the left until； in the rearview mirror； he saw the tyrannosaur give a final roar and turn away。
Gennaro slowed the car。 〃Jesus。〃
Muldoon was shaking his head。 〃I could have sworn I hit him the second time。〃
〃I'd say you missed；〃 Gennaro said。
〃Needle must have broken off before the plunger injected。〃
〃Admit it； you missed。〃
〃Yeah；〃 Muldoon said。 He sighed。 〃I missed。 Battery was dead in the damned laser sights。 My fault。 I should have checked it； after it was out all last night。 Let's go back and get more canisters。〃
The Jeep headed north； toward the hotel。 Muldoon picked up the radio。 〃Control。〃
〃Yes；〃 Arnold said。
〃We're heading back to base。〃
The river was now very narrow； and flowing swiftly。 The raft was going faster all the time。 It was starting to feel like an amusement park ride。
〃Whee！〃 Lex yelled； holding on to the gunwale。 〃Faster； faster！〃
Grant squinted； looking forward。 The river was still narrow and dark； but farther ahead he could see the trees ended； and there was bright sunlight beyond； and a distant roaring sound。 The river seemed to end abruptly in a peculiar flat line。 。 。 。
The raft was going still faster； rushing forward。
Grant grabbed for his paddles。
〃What is it？〃
〃It's a waterfall；〃 Grant said。
The raft swept out of the overhanging darkness into brilliant morning sunlight； and raced forward on the swift current toward the lip of the waterfall。 The roar was loud in their ears。 Grant paddled as strongly as he could； but he only succeeded in spinning the boat in circles。 It continued inexorably toward the lip。
Lex leaned toward him。 〃I can't swim！〃 Grant saw that she did not have her life vest clasped； but there was nothing he could do about it； with frightening speed； they came to the edge； and the roar of the waterfall seemed to fill the world。 Grant jammed his oar deep into the water； it catch and hold； right at the lip； the rubber raft shuddered in the current； but they did not go over。 Grant strained against the oar and； looking over the edge； saw the sheer drop of fifty feet down to the surging pool below。
And standing in the surging pool； waiting for them； was the tyrannosaur。
Lex was screaming in panic； and then the boat spun； and the rear end dropped away； spilling them out into air and roaring water； and they fell sickeningly。 Grant flailed his arms in the air； and the world went suddenly silent and slow。
It seemed to him he fell for long minutes； he had time to observe Lex； clutching her orange jacket； falling alongside him； he had time to observe Tim； looking down at the bottom； he had time to observe the frozen white sheet of the waterfall； he had time to observ