Even in Cuvier's 'Tableau Elementaire', and in the first edition of his
great work, the 'Regne Animal', the 'Pongo' is classed as a species of
Baboon. However, so early as 1818, it appears that Cuvier saw reason
to alter this opinion, and to adopt the view suggested several years
before by Blumenbach,* and after him by Tilesius, that the Bornean Pongo
is simply an adult Orang. In 1824, Rudolphi demonstrated, by the
condition of the dentition, more fully and completely than had been
done by his predecessors, that the Orangs described up to that time
were all young animals, and that the skull and teeth of the adult would
probably be such as those seen in the Pongo of Wurmb. In the second
edition of the 'Regne Animal' (1829), Cuvier infers, from the
'proportions of all the parts' and 'the arrangements of the foramina
and sutures of the head,' that the Pongo is the adult of the
Orang-Utan, 'at least of a very closely allied species,' and this
conclusion was eventually placed beyond all doubt by Professor Owen's
Memoir published in the 'Zoological Transactions' for 1835, and by
Temminck in his 'Monographies de Mammalogie'. Temminck's memoir is
remarkable for the completeness of the evidence which it affords as to
the modification which the form of the Orang undergoes according to age
and sex. Tiedemann first published an account of the brain of the
young Orang, while Sandifort, Muller and Schlegel, described the
muscles and the viscera of the adult, and gave the earliest detailed
and trustworthy history of the habits of the great Indian Ape in a
state of nature; and as important additions have been made by later
observers, we are at this moment better acquainted with the adult of
the Orang-Utan, than with that of any of the other greater man-like
Apes.

[footnote] *See Blumenbach, 'Abbildungen Naturhistorichen