CRANIOMETRY. 79 



the facial portion, but in the latter the change is more 

 rapid and relatively much greater than in the former. 



Sex. The differences in the skulls of the sexes are 

 not apparent before adult age, and again diminish as 

 senility advances. In the adult male skull, as already 

 stated, the facial and cranial portions are nearly equal ; 

 in the female skull the cranial portion is the larger. 

 The female skull presents fewer departures from its in- 

 fantile characters than the skull of the male ; this is 

 especially seen in the development of the facial sinuses. 

 The facial angle in the female skull is, as a general rule, 

 less acute than in the skull of the male. The weight of 

 the male skull will average about twelve and a half 

 ounces ; the female skull averages about eleven ounces, 

 making a difference of about 12 per cent, between 

 the male and female skulls. All of the ridges, grooves, 

 and other anatomical points are less prominent in the 

 female skull than in the skull of the male. 



Race. The greatest difference exists in the skulls of 

 the different races, and the study of these differences 

 constitutes the science of craniology. Probably first in 

 importance in the determination of race by a study of the 

 skull is craniometry, or the measurement and proportions 

 of the skull. If a horizontal section is made through 

 the cranium just above the supra-orbital ridges, and the 

 vault removed, the section presented is an oval. If the 

 long diameter of this oval is taken to represent 100. and 

 the transverse diameter measures 80 per cent, or more 

 of the long diameter, the skull is called a broad, or 

 brachycephalic, skull. If the transverse diameter is less 

 than 75 per cent, of the long diameter, the skull is called 

 a narrow, or dolichocephalic, skull. If the transverse 

 diameter measures from 75 to 80 per cent, of the long 

 diameter, the skull is called mesocephalic, a term sug- 



