424 CLASS MAMMALIA. 



will seek his prey by day and by night ; and his eye-pupil 

 is capable of either shape, and in the twilight or dark, its 

 colour is like a blue-green flame. This remark he made, 

 while drawing a specimen of a large Bengal Tiger at New 

 York. The room of the menagerie in which it was placed 

 was generally rather dark, and at the time was rendered 

 more so by the gloominess of the weather. The animal was 

 exceedingly vicious, endeavouring, occasionally, to strike 

 his keeper ; yet he lay in a stately, and, seemingly, uncon- 

 cerned attitude, with the cleft pupils of his eyes fixed upon 

 the Major while drawing: but if a person passed near him, 

 they were changed instantly into a disk, and their colour 

 altered from yellow-green to blue-green. To this facility 

 of expansion and contraction of the pupils, which, in this 

 instance, resulted from a mental excitement, and not from 

 any alteration in the degree of light, may be attributed the 

 diurnal habits of the Tiger, as also his disregard of night- 

 fires ; while the Lion, whose eyes are not calculated for the 

 glare of day, cannot bear the effect of firelight in the dark. 



The Puma has the pupil constantly circular ; yet this 

 animal is as dangerous by day as by night ; or, to speak 

 more correctly, he will hunt his prey while the sun is above 

 the horizon. 



Of the Lynxes that are found in the United States, that 

 called by the furriers the Chat Cervier, has complete Cats' 

 eyes ; while the Felis Canadensis, which is so nearly allied to 

 it, as at most to be a mere variety, has round pupils, yet 

 the habits of both are similar. 



The Angora Cat, when in little light, has the eye-pupils 

 nearly, if not quite circular ; they form an ellipsis more and 

 more narrow as the light increases, till when exposed to the 

 sun they are almost linear. 



If we refer to other genera, we find considerable variety 

 in this particular. To select a few : the genus canis has 

 some species with circular, and others with oval pupils ; 



