The last lower molar (wisdom tooth) of the gibbon is like that of man, quadri-tuberculate.
But yet it is not strange, for, as I told you, it was a wisdom tooth.
The wisdom tooth seems to be in a state of retrogressive evolution among several populations.
The third molar, or "wisdom tooth," is the last to be cut, and does not appear until about the twenty-first year.
wisdom tooth wis·dom tooth (wĭz'dəm)
The third molar tooth on both sides of each jaw that erupts from the 17th to the 23rd year.