NO. 1495. OBSERVATIONS ON ORANG SKULLS— HRDLICKA. 549 



The forehead, while more or les.s sloping- backward, shows always 

 a good median convexity; in the old males, however, this is nearly 

 obscured by the approximated and prominent temporal ridges. 



The features of the vault of paramount interest are the temporal 

 ridges, and the various aspects under which they were found gave rise 

 to much confusion in the earlier contributions on orang craniology and 

 orang species. Doctor Abbott's series of crania shows clearly many 

 important points concerning these features. Up to the completion of 

 permanent dentition the temporal lines are seen to be well apart all along 

 the median line and resemble in every way those in man. During late 

 adolescence, however, these ridges show a rapid approach toward the 

 interparietal articulation and develop into lines of pronounced rough- 

 ness in the females and into irregularly elevated ridges in the males. 

 In most females they evolve no further than just indicated (as, for 

 example, in Nos. 142193, 142169, 142185, 142186, and 142191), but in 

 some they approach near to junction in the median line (No. 142190), 

 and in othiu's the}^ join for a variable distance from the vertex to the 

 obelion and form a single, low (1 to 8 mm.), sagittal crest, which some- 

 times shows b}" a median groove the line of previous separation (Nos. 

 142170, 142187, and 142182). In males of this series the junction of 

 the advancing rough lines or ridges has taken place in all that reached 

 very near or into adult life (Nos. 142181 to 142189), forming eventu- 

 all}" a pronounced sagittal crest which extends over a part of the frontal 

 bone, rises at its highest point to from 1 to 2 cm. in height, and offers 

 a greatly enlarged surface for the attachment of the temporal muscles. 



The gradual advance mesiad of the two temporal rid^-es with the 

 development of the muscles of mastication, the formation at last of the 

 single crest, and the complete disappearance of all traces of the earlier 

 ridges over the parietal bones, constitute a series of the most interesting- 

 phenomena in the morpholog}' of the orang skull; and they throw at 

 the same time light on the origin and significance of those abnormally 

 high temporal ridges met with in other animals, and occasionally in the 

 human cranium." 



The Jamhdofd crests^ serving for the attachment of temporal as well 

 as occipital muscles, develop in both sexes of orangs much earlier 

 than the sagittal. They reach jointly from mastoid to mastoid, form- 

 ing at lambda a pronounced, rough, triangular tuberosity. In males 

 these crests also, like the sagittal ones, reach much greater propor- 

 tions than in females. Thej" cause a verv early closure of the lamb- 

 doid suture. 



The vertical occipital ridge js comparatively moderate, probably 

 never rising above 4 mm. above the surface of the neighboring bone, 

 and usually being lower. It is more developed in the males. 



«See A Painted Skeleton from Northern Mexico, by the present writer, American 

 Anthropologist, u. s.. Ill, September-December. 1901. 



