Too Long; Didn't Read
Walter Harkness, piloting his ship to a slow, safe landing on a new world, had watched his instruments with care. He had seen the outer pressure build up to that of the air of Earth; the spectro-analyzer had shown nitrogen preponderating, with sufficient oxygen to support life. And, below him, a monstrous thing that flopped hurriedly away on leather wings had told him that life was there.