MISSING LINKS 
is thus seen. Ovycteropus feeds upon ants and it is said 
to impatiently thump with its heavy tail before com- 
mencing operations upon an ant hill; this throws the 
small inhabitants into such a panic that they run 
hither and thither in their confusion and pour out into 
the jaws of their foe. As it feeds on ants it is not sur- 
prising to find that Orycteropus has a particularly long 
and viscid tongue like the tongue of other formicivorous 
creatures. It is surprising, however, to find in its 
mouth, besides'a long tongue, an extensive range of 
teeth. Other ant-eating creatures, for instance the 
anteater, have no teeth. One is disposed to wonder 
if this unexpected array of teeth is not an inheritance 
from the not very remote days when the Orycteropus, 
so to speak, chewed the cud like an ox. The mystery 
of its origin is one upon which but little light has been 
thrown. While the discovery of numerous fossil links 
bind together other groups of mammals, no such con- 
nexions are forthcoming in the case of our aard vark. 
It is an isolated and friendless type declining to be 
allied even to its neighbour, the Mamis or pangolin. 
The old idea that it came near to the ant-eater of America 
has long since been exploded. Probably it is not an 
exaggeration to say that no two mammals are further 
apart than these two. The only hints that we seem 
able to get are in the brain. The nervous system 
generally among animals is an exceedingly conserva- 
tive system, changing but slightly with other changes, 
and then showing up unexpected likenesses in beasts 
apparently remote. It has been pointed out that the 
brain of the Orycteropus is singularly like that of an 
ungulate animal; and it is perhaps to these creatures 
that Orycteropus shows the most likeness. In the 
meantime there are at least two distinct species of 
-aard vark found in Africa, a northern and a southern 
form, while in former times, as shown by its fossil 
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