ERUPTION OF THE PERMANENT TEETH 147 



in the eruption of the teeth, in the number of good sets present, 

 and in the average number of bad teeth. As it is, the segregation 

 by cephahc and facial indices gives considerable difference in all 

 three of these conditions. 



The two types are segregated by putting those with a cephalic 

 index below 80 and a facial index below 120 in one group, and those 

 with a cephalic index of 80 and over and a facial index of 120 and 

 over in another, and the remainder, or those with a cephalic index 

 of 80 and over and a facial index of 120 and less, or those with a 

 cephalic index of 80 and less and a facial index of 120 and over, 

 in a third group. The three will be called the hyper-onto-morph, 

 hypo-onto-morph and remainder. Below the age of 1 1 years the 

 dividing figure of the cephalic index is 81 instead of 80. 



1 . The average number of teeth 



The Filipinos from 5 to 10 years of age may be neglected be- 

 cause of the few individuals who come under observation. The 

 average number of teeth erupted among the German and American 

 boys from 5 to 10 years of age is 



Hyper 9.87 Hypo 9.14 Remainder 9.45 



The average number of teeth erupted in all the groups from 1 1 

 to 16 years of age, including both sexes, is 



Hyper 26.6 Hypo 24.1 Remainder 25.4 



The hyper- is more precocious than the hypo- from 10 to 16 

 years of age. It is therefore evident that the hyper-, at all ages, 

 is more precocious in the eruption of the permanent teeth than 

 the hypo-, and this difference amounts to one or more teeth. 



2. The percentage of good sets of teeth 



The percentage of good sets of teeth among the German and 

 American boys and girls from 5 to 10 years of age is 



Hyper 80.33 Hypo 80.98 Remainder 82.8 



