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XIII. Osteological Contributions to the Natural History of the Chimpanzees (Troglodytes) 
and Orangs (Pithecus)—No. VI. Characters of the Skull of the Male Pithecus 
Morio, with Remarks on the Varieties of the Male Pithecus Satyrus. By Professor 
Owen, F.R.S., F.Z.S8. &c. 
Read December 9, 1856. 
AT the Meeting of the Zoological Society for scientific business, held on the evening 
of October 25, 1836, I communicated a description of the skull of an adult Orang- 
utan, which, on account of its small size, but more especially from the proportions of 
the teeth, I was led to regard as appertaining to a species distinct from either of the 
varieties of the then known larger species of Orang-utan (Pithecus Satyrus), indicated 
by the names Pithecus Wurmbii and Pithecus Abelii. 
For the smaller species of Orang—with canine teeth relatively less in proportion to 
the incisors than in the female of the Pith. Satyrus, with the molar teeth relatively 
larger in proportion to the size of the skull, whilst the superior incisors were nearly as 
large, and the inferior incisors quite as large, as those of the males of the great Pith, 
Satyrus,—I proposed the name of Pithecus Morio. 
No record of the sex of the individual from which the skull in question had been 
derived was obtainable. My own belief was that it belonged to a female Orang; and 
in a letter on the subject, printed in the ‘Revue Zoologique,’ 1839, p. 38, in reply to 
a paper by M. Dumortier’, I particularly compared the skull on which the Pithecus 
Morio had been founded with the skull of the adult female of the Pith. Satyrus (var. 
Wurmbu), and showed that the canine teeth of the Pith. Morio were relatively smaller, 
the molars relatively larger, the cranium being absolutely less, with the occiput rounded 
and convex instead of being flattened, and with the temporal ridges wider apart. 
Various have been the subsequent comments of naturalists on the new species, and 
the evidence on which it was proposed. Mr. Blyth, in his ‘‘ Remarks on the different 
species of Orang-utan’,” states that he ‘‘ inclines to infer that Mr. Owen’s specimen is 
the skull of a male animal, chiefly from the greater depth of the alveoli” (p. 3), as 
compared with the skull of a known aged female Pith. Morio which died at Calcutta, 
and the skin and skull of which are preserved in the Museum of the Asiatic Society. 
Mr. Blyth gives figures of a side- and of a front-view of the skull of the above old 
female Pith. Morio (op. cit. pls. 7 & 8). The comparison of these figures with mine, 
published in the 2nd volume of the Zoological Society’s Transactions, confirmed me in 
! « Notice sur les Modifications du Crane de l’Ourang-outang,” Bulletins de l’Académie Royale de Bruxelles 
tom. v. 1838. 
* Journal of the Asiatic Society of Bengal. I quote from a private copy, without date, of the Memoir, 
VOL. IV.—PART V. 28 
