154 THE TOWER MENAGERIE. 
The species to which the beautiful pair in the Mena- 
gerie belong has all the habits of its group. It is 
characterized by the clear fulvous brown colour of the 
upper surface of the body and outer side of the limbs, 
gradually becoming lighter on the under and inner sur- 
faces, and deepening in its shade towards the tail, the 
greater part of which is nearly black. The muzzle and 
the hands are bluish black. The male has the whole of 
the forehead, the sides of the cheeks, and the under part 
of the lower lip covered with a white fur, which in the 
female is of a blackish gray and much less developed ; 
her general colour is also of a lighter tinge. This 
remarkable difference would lead us to question the 
specific identity of the two animals, were we not assured 
by M. F. Cuvier that he had verified the fact by what is 
usually regarded as an unequivocal test. Mr. M‘Leay 
has, however, thrown considerable doubt upon the accu- 
racy of the inference thus attempted to be drawn, by 
exhibiting to the Linnean Society a female, in whom the 
white fur of the head was as dictinctly developed as in 
her male companion. The whole of the species of this 
group require, in fact, an accurate revision. 
