A campaign against Ythri would demand an enormous fleet, gathered from everywhere in the Empire. No such thing had been publicly seen or heard of, though rumors flew. But of course units guarding the border systems had been openly reinforced as the crisis sharpened, and drills and practice maneuvers went on apace.

Orbiting Pax at ten astronomical units, the Planet-class cruisers Thor and Ansa flung blank shells and torpedoes at each other’s force screens, pierced these latter with laser beams that tried to hold on a single spot of hull for as long as an energy blast would have taken to gnaw through armor, exploded magnesium flares whose brilliance represented lethal radiation, dodged about on gray thrust, wove in and out of hyperdrive phase, used every trick in the book and a few which the high command hoped had not yet gotten into Ythrian books. Meanwhile the Comet- and Meteor-class boats they mothered were similarly busy.

To stimulate effort, a prize had been announced. That vessel the computers judged victorious would proceed with her auxiliaries to Esperance, where the crew would get a week’s liberty.

Ansa won. She broadcast a jubilant recall. Half a million kilometers away, an engine awoke in the Meteor which her captain had dubbed Hooting Star.

“Resurrected at last!” Lieutenant (j.g.) Philippe Rochefort exulted. “And in glory at that.”

“And unearned.” The fire control officer, CPO Wa Chaou of Cynthia, grinned. His small white-furred body crouched on the table he had been cleaning after a meal; his bushy tail quivered like the whiskers around his blue-masked muzzle.

“What the muck you mean, ‘unearned’?” the engineer-computerman, CPO Abdullah Helu, grumbled: a lean, middle-aged careerist from Huy Braseal. “Playing dead for three mortal days is beyond the call of duty.” The boat had theoretically been destroyed in a dogfight and drifting free, as a real wreck would, to complicate life for detector technicians.

“Especially when the poker game cleaned and reamed you, eh?” Wa Chaou gibed.

“I won’t play with you again, sir,” Helu said to the captain-pilot. “No offense. You’re just too mucking talented.”

“Only luck,” Rochefort answered. “Same as it was only luck that threw such odds against us. The boat acquitted herself well. As you did afterward, over the chips. Better luck to both next time.”

She was his first, new and shiny command — he having recently been promoted from ensign for audacity in a rescue operation — and he was anxious for her to make a good showing. No matter how inevitable under the circumstances, defeat had hurt.

But they were on the top team; and they’d accounted for two opposition craft, plus tying up three more for a while that must have been used to advantage elsewhere; and now they were bound back to Ansa and thence to Esperance, where he knew enough girls that dates were a statistical certainty.

The little cabin trembled and hummed with driving energies. Air gusted from ventilators, smelling of oil and of recycling chemicals. A Meteor was designed for high acceleration’ under both relativistic and hyperdrive conditions; for accurate placement of nuclear-headed torpedoes; and for no more comfort than minimally essential to the continued efficiency of personnel.

Yet space lay around the viewports in a glory of stars, diamond-keen, unwinking, many-colored, crowding an infinitely clear blackness rill they merged in the argent torrent of the Milky Way or the dim mysterious cloudlets which were sister galaxies. Rochefort wanted to sit, look, let soul follow gaze outward into God’s temple the universe. He could have done so, too; the boat was running on full automatic. But better demonstrate to the others that he was a conscientious as well as an easy-going officer. He turned the viewer back on which he had been using when the message came.

A canned lecture was barely under way. A human xenologist stood in the screen and intoned:

“Warm-blooded, feathered, and flying, the Ythrians are not birds; they bring their young forth viviparously after a gestation of four and a half months; they do not have beaks, but lips and teeth. Nor are they mammals; they grow no hair and secrete no milk; those lips have developed for parents to feed infants by regurgitation. And while the antlibranchs might suggest fish gills, they are not meant for water but for—”

“Oh, no!” Helu exclaimed. “Sir, won’t you have time to study later? Devil knows how many more weeks we’ll lie in orbit doing nothing.”

“War may erupt at any minute,” Wa Chaou said.

“And if and when, who cares how the enemy looks or what his love life is? His ships are about like ours, and that’s all we’re ever likely to see.”

“Oh, you have a direct line to the future?” the Cynthian murmured.

Rochefort stopped the tape and snapped, “I’ll put the sound on tight beam if you want. But a knowledge of the enemy’s nature might make the quantum of difference that saves us when the real thing happens. I suggest you watch too.”

“Er, I think I should check out Number Three oscillator, long’s we’re not traveling faster-than-light,” Helu said, and withdrew into the engine room. Wa Chaou settled down by Rochefort.

The lieutenant smiled. He refrained from telling the Cynthian, You’re a good little chap. Did you enlist to get away from the domination of irascible females on your home planet?

His thought went on: The reproductive pattern — sexual characteristics, requirements of the young — does seem to determine most of the basics in any intelligent species. As if the cynic’s remark were true, that an organism is simply a DNA molecule’s way of making more DNA molecules. Or whatever the chemicals of heredity may be on a given world… But no, a Jerusalem Catholic can’t believe that. Biological evolution inclines, it does not compel.

“Let’s see how the Ythrians work,” he said aloud, reaching for the switch.

“Don’t you already know, sir?” Wa Chaou asked.

“Not really. So many sophont races, in that bit of space we’ve sort of explored. And I’ve been busy familiarizing myself with my new duties.” Rochefort chuckled. “And, be it admitted, enjoying what leaves I could get.”

He reactivated the screen. It showed an Ythrian walking on the feet that grew from his wings: a comparatively slow, jerky gait, no good for real distances. The being stopped, lowered hands to ground, and stood on them. He lifted his wings, and suddenly he was splendid.

Beneath, on either side, were slits in column. As the wings rose, the feathery operculum-like flaps which protected them were drawn back. The slits widened until, at full extension, they gaped like purple mouths. The view became a closeup. Thin-skinned tissues, intricately wrinkled, lay behind a. curtain of cilia which must be for screening out dust.

When the wings lowered, the slits were forced shut again, bellows fashion. The lecturer’s voice said: “This is what allows so heavy a body, under Terra-type weight and gas density, to fly. Ythrians attain more than twice the mass of the largest possible airborne creature on similar planets elsewhere. The antlibranchs, pumped by the wing-strokes, take in oxygen under pressure to feed it directly to the bloodstream. Thus they supplement lungs which themselves more or less resemble those of ordinary land animals. The Ythrian acquires the power needed to get aloft and, indeed, fly with rapidity and grace.”

The view drew back. The creature in the holograph flapped strongly and rocketed upward.

“Of course,” the dry voice said, “this energy must come from a correspondingly accelerated metabolism. Unless prevented from flying, the Ythrian is a voracious eater. Aside from certain sweet fruits, he is strictly carnivorous. His appetite has doubtless reinforced the usual carnivore tendency to live in small, well-separated groups, each occupying a wide territory which instinct makes it defend against all intruders.