A CLINICAL STUDY OF THE SKULL. 69 



face, probably to unite with the deep temporal veins. The spheno- 

 palatine foramina are relatively of large size in the skull of the 

 young subject. In an adult Tchutchi skulP these foramina were 

 G""" in diameter. 



The foramina of the vertex are few in number. The parietal 

 foramina may be larger than usual, or they may disappear and 

 abrupt openings may occur through the outer plate so as to expose 

 the diploe along the line of the temporal ridge. They are more 

 common on the frontal portion of the crest than elsewhere. 



The variations of the front of the skull pertain to the anterior 

 lacerated foramina, the infra-orbital foramina, and the opening along 

 the line of the frontal suture. The differences in the anterior lac- 

 erated foramina are chiefly those of symmetry. The infra-orbital 

 foramina vary chiefly in the manner by which the fissures of the 

 maxilla close and the extent of the forward growth of the malar 

 bone. Foramina occasionally appear at the median line, of the 

 forehead, and are doubtless due to the partial failure of the two 

 halves of the frontal bone entirely to unite. 



The foramina which transmit important structure are commonly 

 modified from fissures, and in reversion easily assume again the 

 stage of the fissure. Since they so originate, it is easy to account 

 for their presence near the margins of fissures (as is seen in the for- 

 amen ovale and foramen spinosum, near the fissure between the 

 sphenoidal and petrosal elements). In like manner the parietal 

 foramina appear at the side of the sagittal suture. Exceptions to 

 this rule are seen in a small canal (occasionally present) which 

 transmits a vein between the squamosal and parietal bones, and in 

 a foramen in a Peruvian skull.^ 



1 No. 1030, A. N. S. 



'No. 17, from San Mateo, which exhibits an opening between the frontal 

 and parietal bones. 



