NO. 1521. MEASUREMENTS OF CRANIAL FOSSJE—HRDLlC^KA. 



199 



In seven of the ten series of human adults the average of the sum 

 of the lengths of the three cerebral fosste on the left exceeds that of 

 the right side by from 1 to 3 millimeters. There is therefore a clear, 

 though small, excess of fossal length on the left in the mass of human 

 adult crania. In two series the averages are equal ; while in one 

 series, the brachy cephalic Indians, an excess (2 mm.) is shown for the 

 right side. In the human young, anthropoid apes, and monkeys, the 

 difference in the averages are nil, or not exceeding half a millimeter. 



Individually the sum of the lengths of the three fossiv on each side 

 was as follows : 



('ornbined letiglh of cereJiral fosi^te on tlie iico sides. 



Subjects. 



Whites, males : 



liolieluicephals 



Mesi)er])hals 



J?raeli\( fiilials 



Whites, femnles : 



I>(ilieh(iceiihals 



Mesocephals 



Kraehyeeiihals 



Indians, males : 



Diilicliocciilials 



Brachyee|)hals 



Negroes, males : 



Dolicho- to mesocephals . 

 Negroes, females : 



Dolicho- to me.socephals. . 



Human fetuses and Youn£ 



Anthropoid apes . . . . 

 Monkeys and lemur. 



Lefto+w+ps 

 longer than 

 right in — 



Fir cent. 



[a, anterior; m, middle; ps, postero-superior fossa.] 



These figures reveal several facts of some importance. Among the 

 human adults the brachycephals show all through a remarkably 

 greater proportion of larger fossal length on the right and smaller on 

 the left side than the mesocephals, and especially the dolichocephals. 

 And similarly large percentage of longer right fossal length exists in 

 the human young, the anthropoid apes, and the monkeys and lemur. 

 Sex shows no particular difference, and the influence of race is small, 

 if any. The brachycephals stand in this feature decidedlv nearer the 

 human young and the other primates than man, than the dolichoceph- 

 als. It is, of course, possible that the prevalence of a greater fossal 

 length on the right side is due to different causes in these several 

 groups, but more likely- there is some relation in these phenomena. 



