World of the Dark 



Vancouver and southward through the mountains of the 

 Appalachian System and along the higher plateaus and mountain 

 ranges of the West as far as Central Mexico. I have specimens 

 taken in the Sierra Madre of Chihuahua. The identification 

 of the species may easily be made by means of the figure 

 on our plate. 



THE WORLD OF THE DARK 



" Sorrowing we beheld 



The night come on; but soon did night display 



More wonders than it veil'd; innumerous tribes 



From the wood-cover swarm'd, and darkness made 



Their beauties visible." 



Southey. 



There are two worlds; the world of sunshine, and the world 

 of the dark. Most of us are more or less familiarly acquainted 

 with the first; very few of us are well acquainted with the latter. 

 Our eyes are well adapted to serve us in the daylight, but they 

 do not serve us as well in the dark, and, we therefore fail to 

 know, unless we patiently study them/'what wonders this 

 world of the dark holds within itself. /There are whole armies 

 of living things, which, when we go t6 sleep, begin to awaken; 

 and when we awaken, go to sleep. The eyes of the creatures 

 of the dark are adapted to seeing with less light than our eyes 

 require. The broad daylight dazzles and confounds them. 

 Sunshine has much the same effect upon them that darkness has 

 upon us. Our twilight is their morning; our midnight is their 

 noonday. 



This is true even of many of the higher vertebrates. The 

 lemurs, which are a low family of simians, are nocturnal in their 

 habits. So also is the Aye-Aye of Madagascar, and that curious 

 little member of the monkey tribe known as the Specter 

 (Tarsius spectrum). No one can see the great eyes of these 

 creatures without realizing at a glance that they love what we 

 call darkness better than what we call light, though they are 

 far from being evil-doers. The great family of the cats are 

 principally nocturnal in their habits. Their eyes are capable of 

 being used in daylight, for the beautifully contracting and ex- 

 panding iris modifies the amount of light admitted to the retina 



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