CLIMBING ORGANS 
vation will doubtless settle the point. It has been 
suggested that they are of the nature of “ climbing 
irons,” and aid the lemur in barking up a tree; but 
with an excellent and delicately fashioned hand such 
adjuncts appear to be unnecessary. Besides, why 
should the structure be different in the two sexes, if it 
be of this or an analogous direct use. More probably 
it is one of those mysterious marks of sex which often 
have no ascertained uses, such as the moustaches of the 
male man and the different colours of the plumage in 
many birds. 
THE UNGULATA, OR HOOFED MAMMALS 
Horns and hoofs are the distinguishing feature of this 
large order of mammals; they are, furthermore, 
graminivorous, or, at least, vegetarian in habit, and, 
as a rule, walk upon the tips of the toes. But an inspec- 
tion of the various Ungulates contained in the menagerie 
in London will show that some of these characters do 
not absolutely define every member of the order. The 
Hyrax, for example, walks firmly upon the sole of its 
foot, and has no horns. The elephant has no horns. 
These two animals are, in fact, representatives of ° 
Ungulates of a more primitive structure than the rest. 
The very earliest known members of the order, now 
extinct, had not acquired the more typical ungulate 
characteristics of their descendants of to-day. In many 
respects they showed symptoms of fading into other 
orders of mammals, particularly the Creodonta, the 
ancestors of the Carnivora of the present day. It 
remains, however, the fact that, though some Ungulates 
have not got horns, the existence of horns is absolutely 
confined to this order. In zoological classification even 
the veriest beginner soon learns that Nature draws no 
hard and fast lines, and that when an attempt to make 
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