Bright-colored eyes in many species are probably due, like ornaments and gaudy plumage, to sexual selection. The quality of shining in the dark, however, possessed by many nocturnal and semi-nocturnal species, has always, I believe, a hostile purpose. When found in inoffensive species, as, for instance, in the lemurs, it can only be attributed to mimicry, and this would be a parallel case with butterflies mimicking the brilliant “warning colors” of other species on which birds do not prey. Cats amongst mammals, and owls amongst birds, have been most highly favored; but to the owls the palm must be given. The feline eyes, as of a puma or wild cat, blazing with wrath, are wonderful to see; sometimes the sight of them affects one like an electric shock; but for intense brilliance and quick changes, the dark orbs kindling with the startling suddenness of a cloud illuminated by flashes of lightning, the yellow globes of the owl are unparalleled. Some readers might think my language exaggerated. Descriptions of bright sunsets and of storms with thunder and lightning would, no doubt, sound extravagant to one who had never witnessed these phenomena. Those only who spend years “conversing with wild animals in desert places,” to quote Azara’s words, know that, as with the atmosphere, so with animal life, there are special moments; and that a creature presenting a very sorry appearance dead in a museum, or living in captivity, may, when hard pressed and fighting for life in its own fastness, be sublimed by its fury into a weird and terrible object.