 Why was the large Kallerian not chosen for the journey?
My three staff men, Auchinleck, Stebbins and Ludlow, walked shieldwise in front of me. The aliens came in every shape and form, in all colors and textures—and all of them eager for a Corrigan contract. There was a lidless eye at the top of his head and five lidded ones, one above each arm. We needed a green Regulan in our show; the last one had quit four years ago. But just because we needed him didn't mean we had to be extravagant in hiring him. A Terraphile alien who goes to the extent of rechristening himself with a Terran monicker would work for nothing, or even pay us, just so long as we let him get to Earth. He was followed by a roly-poly blue-skinned humanoid from Donovan's Planet, four feet high and five hundred pounds heavy. We already had a couple of his species in the show, but they made good crowd-pleasers, being so plump and cheerful. I passed him along to Auchinleck to sign at anything short of top rate. It was the isolationism of the late 29th century that turned me into the successful proprietor of Corrigan's Institute, after some years as an impoverished carnival man in the Betelgeuse system. Before then, anyone could visit Earth. After the gate clanged down, a non-terrestrial could only get onto Sol III as a specimen in a scientific collection—in short, as an exhibit in a zoo. At the same time, we had turned away a dozen ursinoids, fifty of the reptilian natives of Ghryne, seven Sirian spiders, and no less than nineteen chlorine-breathing Procyonites wearing gas masks. It was also my sad duty to nix a Vegan who was negotiating through a Ghrynian agent. "I happen to be a representative of the only Earthlike race that exists anywhere in the Galaxy but on Earth itself. The first harbinger of woe turned up after lunch in the person of a Kallerian. The Kallerian was the sixth applicant that afternoon. I had turned away three more ursinoids, hired a vegetable from Miazan, and said no to a scaly pseudo-armadillo from one of the Delta Worlds. Hardly had the 'dillo scuttled dejectedly out of my office when the Kallerian came striding in, not even waiting for Stebbins to admit him officially. I said, "You'll have to understand, Freeman Heraal, that it's not our policy to maintain more than a few members of each species at our Institute. I showed him that we were already carrying four Kallerians, and that was more than plenty.
 There were already four Kallerians in inventory.
 There were already four Kallerians in inventory.  His species was too large to travel in the group.  He was argumentative during the interview process.  His payout demands  exceeded their budget.