392 CATS’ EYES CHAP. 
: we 
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—ain 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 
Kyra, 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 honess—there are distinct indications of these 
spots. It is evident, therefore, that there are erounds 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. 1898, p. 719. 
* 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. 
