392 CATS' EYES CHAP. 



made by Dr. Lindsay Johnson, 1 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, 2 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, 3 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 occasion- 

 ally 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 re- 

 garding 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 



1 "On the Pupils of the Felidae," Proc. Zool. Soc. 1894, p. 481. 



2 "Observations ... on the Seal's Eye," Proc. Zool. Soc. 1893, p. 719. 



3 It is noteworthy that in the Tiger some of the stripes have pale centres and 

 are thus like spots pulled out, while there are also small black spots. . 



