360 MR. R. OWEN ON THE OSTEOLOGY OF 
separates it in the upper jaw from the small deciduous incisors, which, together with 
the laniary tooth, are partially protruded from their sockets. The large foramina behind 
the incisor and laniary teeth afford a sure indication of the presence of the permanent 
series, which are still concealed within the jaws ; and these are found, upon a removal 
of the parietes of the alveoli, lodged in the following order. 
In the upper jaw the second or smaller incisor is the most advanced in its progress, 
its middle projecting point being just within the orifice leading to the cavity in which 
it is lodged. Its posterior surface is directed inwards, or mesiad, and is placed at right 
angles to the corresponding surface of the first or great incisor, immediately behind 
which it is situated, and from which it is separated by a thin lamella of bone. The 
entire crown and about half a line of the fang are formed. The great crown of the first 
incisor has almost a horizontal position, and occupies the whole breadth of the os in- 
cisivum. 
Behind the second incisor comes, not the laniary, but the crown of the first bicuspis, 
separated from the incisor by a lamina of bone about a line in thickness. Then, deeper 
in the jaw and posterior to the first bicuspis, is the crown of the second bicuspis. In each 
of these about one third of a line of the fang is already formed. The first true molar has 
already taken its place in the dental series ; but its recent formation is shown in the 
shortness of the fangs and the wide entry to their cavity, in which the pulp was con- 
tained. The crown only of the second true molar is formed, which is lodged deep in 
the jaw, with the grinding surface, as in the undeveloped teeth of the Elephant, directed 
backwards in the upper jaw, and forwards in the lower. This surface has, however, all 
the characteristic markings of the corresponding tooth in the old Orang. A large round 
foramen leads to the concealed cavity in which it is lodged. The socket of the third 
molar, or dens sapientie, is widely open, but contains as yet only a little shrivelled 
membrane with specks of calcareous matter, the remains of the pulpy, and commence- 
ment of the bony, rudiments of the future tooth. 
In the lower jaw the crowns of the permanent teeth are situated in nearly the same 
relative position as in the upper. The second incisor is immediately behind and a little 
above the first. The conical extremity of the crown of the great laniary is lodged deep 
in the jaw, with the apex projecting into the interval between the second incisor and 
first bicuspis. The crowns of the bicuspides, which in the upper jaw have the grinding 
surface directed outwardly, in the lower jaw have the same surface turned in the oppo- 
site direction. The great crown of the second molar is equally advanced with that of 
the upper jaw; and in like manner, of the third molar, the cavity only and a small 
shrivelled rudiment remain. 
It is impossible to contemplate the apparent confusion in which these huge succes- 
sors of the temporary teeth are crowded in the jaws, without a feeling of surprise and 
admiration at the regular arrangement they present when their evolution is completed. 
It would seem as if the incisors must have taken up the same relative position as those 

