32 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



SEX AND SIDE IN JUVENILE BONES 



Differences during the growth period in the incidence and develop- 

 ment of the hypotrochanteric fossa in the two sexes may exist, but 

 our body-sexed material is very inadequate, and reliable sexing of 

 juvenile bones themselves, except in the later stages of adolescence, 

 is impossible. 



As to the right and left bones, some differences in the fossa appear, 

 but not with sufficient preponderance to have any definite significance. 

 The most suitable group for showing the conditions is that of the 

 North American Indians. In condensed form, the group shows the 

 following : 



Hypotrochanteric Fossa on the Two Sides in Juvenile North American Indians 



Age group and no. of femora 



None 



Trace 

 to 



small 



Moderate 



to 

 medium 



Above 

 medium to 

 pronounced 



Younger children:" 



Right (145) 



Left (138) 



Older children: 



Right (31) 



Left (33) 



Younger adolescents: 



Right (60) 



Left (57) 



Older adolescents: 



Right (81) 



Left (81) 



Percent 



33 I 

 36.2 



16. 1 



15-2 



3 3 

 3-5 



2-5 

 2.5 



50.3 

 46.4 



32 3 

 27-3 



20- 

 12.3 



1 .2 

 4 9 



15 9 

 17-4 



45-2 

 57-6 



48.3 

 47-4 



56.8 

 58.- 



Percent 

 0.7 



6.5 



28. S 

 36.8 



39 5 

 34-6 



" In all the series here the bones are largely pairs. 



There are, it is seen, differences, but they are so irregular that it 

 is hard to recognize any definite tendencies. Elimination of the 

 unpaired bones does not materially change the picture. 



THE FOSSA IN ADULTS 



To learn the full life history of the fossa, in view of what has 

 been seen hitherto it would be desirable to segregate the adult ma- 

 terial into at least three categories, namely, the young adults, the 

 middle-aged, and the old ; but such a division with most of our series 

 would be impossible. It will be feasible, however, to subdivide adults 

 of each racial group on the basis of sex and side. 



To render the data as intelligible as possible, the total number of 

 specimens in each group will first be dealt with as a unit. The results 

 follow : 



