38 BUREAU OF AMERICAN ETHNOLOGY [BULN. 62 
from racial group to group, and even within a single stem of people, 
such as the Indians. On the whole, however, it may be said that in the 
Indian female the mastoid is somewhat more developed than it is in 
the average white woman. Occasionally it is considerably more de- 
veloped, reaching the subaverage or even the average dimensions of 
that of the males in the same tribe. The grade of development of the 
process is of course related to the strength and activity of the sterno- 
cleido-mastoid muscle, to which it gives attachment. Among the 
Munsee the size of the mastoids on the whole is only moderate; yet 
even in this series they rise in one of the female skulls to maleciee 
proportions. 
XIX. MUNSEE CRANIA: MASTOIDS 
10 males 12 females 
Cases Per cent Cases Per cent 
Large’ (masentine)'- 8a sa aekce Pe eee ae eS 1 a0 isl peers tea =) = 
Mediums (masculine) ieee. ate os epee te samen 6 60 1 8 
Submediurn' (dentine) >= os bo 4. eke ee eee 3 30 11 92 
In one of the females (no. 285,309) the apex of the left mastoid is 
bifid. Well developed cases of this anomaly are rare; there are only 
three or four other Indian crania in the large collections of the 
United States National Museum in which it is well represented. In 
another female specimen (no. 285,304) the right mastoid shows a 
peculiar, marked indentation in the middle of its dorsal surface, with 
a groove extending therefrom upward and backward and down- 
ward and backward. 
SUPRAORBITAL RIDGES 
These ridges, as is well known, are sexual characteristics in the 
main; phylogenetically they are the remains of the pronounced 
supraorbital arches of man’s anthropoid ancestors and of early man. 
Like the mastoids they show also considerable individual variation 
in each sex among the Indians, owing to which they occasionally 
fail to afford aid in the determination of the sex of the specimen. 
As a rule they are limited in Indians to the median half to two-thirds 
of the supraorbital space. In the Munsee skulls at hand they are 
markedly developed in only one of the males; in two of the male 
skulls they are small, feminine like, while in two of the female skulls 
they are so developed as to approximate the supraorbital ridges of 
the average male. 
