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 made by Dr. Lindsay Johnson, who found that out of 180 Domestic Cats 111 had round pupils, and that in 19 the shape was a pointed oval, intermediate conditions being offered by the rest. These 180 comprised males and females of many varieties. When the pupil of the Cat's eye contracts, it forms a vertical slit with two pin holes, one at each end, through which alone light appears to enter. In the Genet and the Civet the contraction of the pupil is as in the Cat. In the Lion, Tiger—in fact apparently in all the large Cats—the pupil retains its circular shape even when contraction is fully effected. Dr. Johnson has, furthermore, made some interesting experiments upon the Seal's eye—a creature which has, of course, to exert its powers of vision in two media, and from one to the other. This is effected by dilatation of the pupil when in the water, and its contraction to a vertical slit with parallel margins and rounded ends when in the air, the contraction being to some extent at least under the influence of the animal's will.

The coloration of these creatures is very varied: spots of black, or bordered with black upon a more or less tawny ground-colour, is the prevailing pattern. Stripes are also met with, as in the Tiger, but these are usually cross stripes, while in the related Viverridae there are many examples of longitudinal stripes. Finally, many Cats, as for instance the Puma and the Eyra, are "self-coloured"—have, that is to say, a uniform tint. Just as the unstriped Horse sometimes shows traces of the former existence of stripes, so the self-coloured Cats are occasionally spotted when young; this is markedly so in the case of the Puma; while the Lion is spotted as a cub, and in the adult—particularly in the lioness—there are distinct indications of these spots. It is evident, therefore, that there are grounds for regarding a spotted condition to be antecedent, at least in some cases, to a uniform colour. There are divers explanations of these hues and of these changes. It is held by many that the coloration has a relation to the habits of the creature: the spotted Cats, it is pointed out, are largely arboreal; this is eminently so with the Jaguar at any rate; and in an arboreal