174 PROFESSOR OWEN ON THE OSTEOLOGY OF 
maxillaries, with concomitant varieties of profile contour,—offering forms and characters 
of cranium intermediate between the two extremes of the crested adult male skulls 
figured in the Zoological Transactions, vol. i. pl. 54, and vol. ii. pl. 32. 
I next proceed to notice some characters in the series of six adult male skulls of the 
large Bornean Orang, which have no parietal crest. 
In the youngest of this series, no. 1100, the temporal ridges are 14 lines apart, yet 
half the crowns of the incisors are worn away ; but the crowns of the canines are nearly 
entire, and the molars are not more abraded than in the crested skull, no. 3 B. The 
lambdoidal ridges are interrupted by the breadth of the space between the temporal 
ridges. 
In the skull no. 1101 (Pl. L. fig. 3), those ridges are 10 lines apart, and are more 
directly continued behind into the lambdoidal ridges: the inner halves of the upper 
molars (fig. 4) and the outer halves of the lower molars are worn into smooth cavities. 
There are styloid processes 3 lines in length. 
In no. 1086, with the molars as much worn as in the preceding skull, the temporal 
ridges are 12 lines apart: there is a low smooth longitudinal rising, not to be called a 
ridge, in the midspace between the ridges. The styloid processes are 3 lines in length. 
The lower molars of this skull are figured in Plate L. fig. 5. 
In no. 1087, the temporal ridges are 10 lines apart, with a low narrow median longi- 
tudinal rising ; the molars are as much worn as in no. 1101, except that the last, owing 
to their unusually small size, have escaped their due share of abrasion. One half of the 
crowns of the canines are worn down: the lambdoidal ridge is strongly developed, and 
the occiput proportionally broad. 
In no. 1131, the grinders are so much worn that the roots protrude from the sockets, 
yet the temporal ridges are 6 lines apart. 
A still greater degree of abrasion is shown by the molars of no. 15, the inner halves 
of the upper ones being ground down to the roots, which project from the sockets: the 
temporal ridges are 3 lines apart. 
The kind and degree of variety in the above series of non-crested skulls are the same 
as in the crested series. My interpretation of the difference of development of the 
temporal muscles, as indicated by the separation or confluence of the temporal ridges 
in these great Orangs, is as follows :—those muscles are closely related, in regard to 
their development beyond a certain size, to the magnitude and use of the canine teeth. 
The great proportional size of these teeth is a characteristic of the male sex; their 
chief use has probably, therefore, a sexual relation. Like the horns of the Bull or the 
antlers of the Deer, they are the weapons by which the males contend for the possession 
of the female. 
Orangs may be born with original differences of disposition, some being more 
courageous, more combative than others. This proneness to fight and conquer is the 
probable concomitant of a superior general robustness of frame, of greater nervous 
