92 ALE§ HRDLICKA 



the typical feminine one. It is larger on the whole and in all its 

 components, it is heavier, and all its muscular insertions as well as 

 other features are more strongly marked or developed. But in no 

 human group is there any regular, precise line of demarcation between 

 the male and female characteristics, taken individually or even col- 

 lectively. In every lot we find male skulls which in some or all of their 

 features are less masculine than the average, and similarly there wiU 

 be female skulls that in some or all of their parts approach the mas- 

 culine. Instead of a sharp dividing line we have interdigitation and 

 continuity, as a result of which in certain cases the sexual identifica- 

 tion of a specimen with all our efforts remains uncertain. In rare 

 cases, even, a female skull may show more pronounced masculine 

 characteristics than some of the less well developed male crania, and 

 vice versa, which may lead to errors in classification. 



On the whole it may be said that an experienced and careful ob- 

 server will have little if any difficulty in correctly identifying over 

 80 per cent of the crania, with which there is neither the lower jaw nor 

 any other part of the skeleton to assist him; that this proportion will 

 approximate 90 per cent where a well-preserved lower jaw is present; 

 and that it will reach over 96 per cent where we have the whole skele- 

 ton. But out of each hundred there will still remain one or two skele- 

 tons which, even though complete, show such indefinite sexual char- 

 acteristics that it will be impossible to identify them as either male or 

 female with certainty. 



Given a skull for sexual identification, the observer notes first the 

 size of the vault as well as that of the face ; a large size speaks normally 

 for a male and a small size for a female. The features observed next, 

 and in the order named, are the supraorbital ridges, the mastoids, the 

 zygomte, the occipital crests, the lower jaw, tJie palate and the teeth, 

 the facial "physiognomy," and the base of the skull. 



The supraorbital ridges are on the average decidedly more developed 

 in the males than in the females. If we should characterize them as 

 we do in practice by the terms "traces," "slight," "moderate," 

 "medium," "pronounced," and "excessive," the male skulls will show 

 ridges from moderate to excessive, while the female skulls will be 

 restricted to those of from traces to moderate. Pronounced or exces- 

 sive ridges do not occur in females, nor are ridges that could be char- 

 acterized as only "traces" to be found in adult males. But we may 

 have "slight" ridges in a male subadult or even adult. 



The mastoids may be "small," "moderate," "medium," "large," 



