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is the close approximation of the teeth one to another serially, 
so that no vacant space (or, as it is technically called, diastema) 
is left between any two adjacent teeth. 
To find a similarity to man in this respect we have again 
to descend through the whole series of Apes, till we come 
to the lower and more aberrant forms of the Half-Apes, and 
there alone, in the little Tarsier of Celebes, we once more meet 
with teeth placed in serial contiguity, as in man. 
3. A third character which may here be mentioned, is one 
exhibited by the masticating surfaces of the larger grinding 
teeth of the upper jaw. We find in Man on the masticating 
surface of each of these teeth an oblique ridge, running from 
the front inner angle of such sm'face outwards, and backwards 
to its hind outer angle. 
This character is found also in the teeth of the Orang, 
Chimpanzee, and Gorilla, but it does not exist in those of the 
Gibbons, nor in those of any of the lower Simiadse. Here, 
then, we seem to come upon a striking character as to affinity 
with man — a character the more deep and significant, in that 
it is hard to see how the presence of this slight ridge should 
be so favourable in the life-struggle as to be independently 
developed in different forms by any mere action of natural 
selection. 
Nevertheless, when we pass to the American Apes we find it 
reappearing in the Spider and Howling Monkeys, and, strange 
to say, even amongst the Half-Apes {e.g. in Arctocebus, Micro- 
cehus, and Galago) the same structure is distinctly developed. 
4. The fourth character is one drawn from the order of the 
succession of the teeth. Each eye-tooth of the second or per- 
manent set is cut in man before the hindmost grinder but one 
makes its appearance. In the Orang, Chimpanzee, and Gorilla, 
all the grinders of the second set make their appearance before 
the canines of the same set. In the Gibbons the canines 
accompany, if they do not precede, the appearance of the hind- 
most grinder, and so far, therefore, these animals seem to 
approximate to the human condition ; but the resemblance is 
of no significance, since it is a condition often found in the 
lower Apes. 
Most of the Gibbons, again, resemble man more than do the 
Orang, Chimpanzee, or Gorilla, or than many of the lower 
Simiadse, in the absence of large saccular dilatations or pouches, 
in connexion with the larynx. 
The shape of the stomach is more human in the Gibbons than 
in the other broad-breastboned apes. 
The Orang has been said to have no uvula, but, as Professor 
Flower has pointed out, it is present, though disguised by the 
extent of development of adjacent membrane. 
