172 PROFESSOR OWEN ON THE OSTEOLOGY OF 
‘« M. Klingenberg’s Museum.—In the skull of an adolescent male S. Satyrus, all the 
permanent molars were in place, and the large canines had nearly got into place: there 
was a well-marked diastema between the canines and premolars in the lower jaw, 
as well as the diastema always present between the canines and incisors of the upper 
jaw: here the maxillo-premaxillary suture had become nearly obliterated ; a small pro- 
portion of its upper part, and that within the nasal cavity, alone remaining open. The 
parietals do not join the frontals on either side. 
“« Adult female.—The lambdoidal, sagittal, and premaxillary sutures were obliterated : 
the canines were small, and these, with the incisors, had been well worn: there was 
scarcely any diastema or vacant space between the canines and bicuspides of the lower 
jaw ; but a well-marked interspace between the canines and incisors in the upper jaw. 
The nasal bone was not compressed in this skull, as in one of the preceding. 
‘“* Baron V. der Capella’s Collection.—Here I saw a singular variety in the skull of an 
adult S. Wurmbii, viz. six molar teeth instead of five on each side of the lower jaw. 
In the skeleton of the adult Sumatran Orang, at the College of Surgeons, there is the 
reverse variety of dentition, only four molars, two true and two false, being developed 
on each side of each jaw. It was this which partly led Dr. Harwood to imagine it to 
be a distinct species from the young Simia Satyrus. 
‘* Museum Senkenbergianum, at Frankfort.—Here I saw the cranium of an adult Orang, 
sex unknown, most probably female, smaller than my S. Morio, the total length being 
7 inches 3 lines: the canines were nearly as feebly developed, the length of the 
enamelled crown being 7 lines; the length of the molar series, upper jaw, was 2 inches 
1 line ; but the middle incisors were as large as in the Morio, the breadth of the crown 
being 64 lines: the principal difference in this cranium arose from the great develop- 
ment of the supra-orbitary ridge, which gave it the character of the skull of the Chim- 
panzee, from which, however, it differed in other essential points.” 
The chief variety in the skulls of the adult males of the large species of Orang is in 
the temporal ridges, depending on the development of the temporal muscles: in some 
(Pl. L. fig. 1) the ridges meet and form a ‘ parietal crest,’ rising above the median line 
of the vertex; in others (Pl. L. fig. 3) they do not meet, but form two low lines or 
ridges, at varying distance from each other in different skulls. 
Of the thirteen skulls of large male Bornean Orangs in the British Museum, seven have 
the parietal crest, and six have the two separate temporal ridges. Both series of skulls 
are fully adult, and show nearly the same differences of age, so far as such differences 
are indicated by the degree of abrasion of the teeth. The presence or absence of the 
parietal ridge clearly does not depend upon the age of the adult. In certain individuals 
only it depends upon age: the temporal ridges do not meet in any of the great male 
Orangs until the permanent canine teeth have come into place; but in many indivi- 
duals those ridges remain separate throughout life, or until a very advanced age. The 
sixth stage, described by M. Dumortier’, is characteristic of the adults of certain indi- 
' Op. cit. p. 7. 
