46 BUREAU OF AMERICAN ETHNOLOGY *[BULL. 62 
greater muscular activity on that side, would be a more satisfactory 
explanation. 
Depressions of the petrous portions.—In examining the petrous parts 
in the usual way, with the skull turned base upward, it is observed 
that in modern men of all races, in the majority of cases, these parts 
are more or less depressed below the niveau of the surrounding parts. 
In reality, of course, the surrounding parts have been pressed out- 
ward by the developing brain, while the prismatic and resistant pet- 
rous parts remained behind. The grade of depression of the petrous 
parts stands generally in close correlation with the size of the middle 
lacerated foramina and is of parallel significance.!. Among the anthro- 
poid apes even a slight depression of the petrous portions is very rare, 
and most frequently, especially in the orang, these portions rise 
slightly abeve the surrounding structures. In the African negro, and 
occasionally in individual skulls of other inferior races, they are level 
with the surrounding parts. In better developed negro skulls, as in 
the majority of those of other primitive peoples, they are slightly to 
moderately depressed. In white men, and in superior skulls in gen- 
eral, the depression is frequently pronounced, especially, it seems, in 
the brachycephals. The Indian stands in a practically intermediate 
position between superior whites and the negroes, and the Munsee 
arenoexception. In two of the skulls the depression is well marked; 
in three males and seven females it is less than the average in whites; 
and in two males and five females it is only sight. The females, it 
will be noted, make a poorer showing in this respect than the males. 
XXXVI. MUNSEE CRANIA: DEPRESSION OF PETROUS PORTIONS 
7 males | 12 females 
Cases Per cent Cases Per cent 
Medium (about as average in whites).............-..-..-.------ 2 29).'| Sore.o sate 3 bte|  Oeree 
Srbmeditm se. see see aigaace serene ea ae ee oa 3 43 7 58 
None or almostimone see neasere sce e eae eee eee ree ae oa ae 2 29 5 42 
Pterygo-basal foramina. Posterior condylic foramina.—Interesting 
features of the base of the skull, to which Gruber and (in this country) 
Harrison Allen have called attention, are the foramina found occasion- 
ally at the base (or proximal part) of the external pterygoid plates. 
These foramina are seldom complete. They may be single, double, 
or even triple. They are formed by a process or by processes of 
bone which proceed upward and backward, and in some cases more 
or less outward, from the border of the external pterygoid plate. 
According to the insertion of these processes, the foramina to which 
1 See Hrdli¢ka, Certain Racial Characteristics of the Base of the Skull, Science, 1901, p. 309; Proc. Assoc. 
Amer. Anatomists, 15th Sess., in Amer. Jour. of Anatomy, 1, 1901-2, pp. 508-9. 
