9<D APES AND MONKEYS 



and in both species the parts of the eye which are white 

 in man are brown in them. But this gradually shades off 

 into a yellow near the base of the optic nerve. As a rule, 

 the kulu has a clear, open visage, with a kindly expression. 

 It is confiding and affectionate to a degree beyond any other 

 animal. It is more intelligent than its confrere, and displays 

 the faculty of reason almost like a human being. 



One important point in which these two types of ape 

 differ is in the scope and quality of their voices. The 

 kulu makes a greater range of vocal sounds. Some of 

 them are soft and musical ; but those uttered by the 

 ntyigo are fewer in number and harsher in quality. One 

 of these sounds resembles the bark of a dog, and another 

 is a sharp, screaming sound. The kulu evinces a certain 

 sense of gratitude, while the ntyigo appears to be almost 

 devoid of that sentiment. There are many traits in which 

 they differ, but human beings, even within the same family 

 circle, also differ in these qualities. The points in which 

 they coincide are many, and, after a brief review of them, 

 we may consider the question of making two species of 

 them or assigning them to the same. 



The skeletons — as we have noted — are the same in 

 form, size, and proportion. Their muscular, nervous, and 

 veinous systems are for the most part the same. The 

 character of their food and the mode of eating are the 

 same in each. In captivity they appear to regard each 

 other as one of their own kind ; but whether they inter- 

 cross or not remains to be learned. 



Such is the sum of the likenesses and the differences 

 between the two extreme types of this genus. With so 



