250 Mr. Home's Observations on the Structure of 
other three are still concealed in the jaw, not being completely 
formed; of the last of these, the first rudiments only are to be 
seen. 
This large tooth, (which may be considered to be a second 
set of teeth,) as the concealed processes enlarge, advances for- 
wards, pushing the other teeth before it : the most anterior of 
these, as soon as its body is worn away, has its fangs removed 
by absorption, and drops out : the same thing takes place with 
the second and third ; and, in this way, room is made for the 
large one to supply the place of all the others. 
The mode in which they succeed one another, is illustrated 
by the annexed drawing of a side view of the jaw, Tab. XIX. 
in which the fangs of the different teeth are exposed ; and the 
body of the third tooth, having been moved forward, as the last 
increased in size, is distinctly seen. 
These peculiarities in the teeth of the Sus JEtbiopicus , led to 
the examination of the teeth of the other species of the same 
genus ; all of which appear to resemble the human grinders, 
only that the last in the jaw has a broader grinding surface 
than the rest, which is common to most quadrupeds. It is 
worthy of remark, that the number in each side of the jaw in 
the common hog is seven ; in the Pecary, six ; in the Baby- 
roussa, five ; and in the Sus JEtbiopicus , till a certain age, 
four. 
It is curious, that one species of a genus should differ so 
widely from all the others, in respect to its teeth ; and should be 
allied to the elephant in the structure of its tusks, the mode of 
formation of the grinding teeth, and the manner in which they 
succeed one another. From these circumstances it appears, 
that the Sus JEtbiopicus , in a natural state, is supplied with a 
