A CLINICAL STUDY OF THE SKULL. 71 



It has been found in one side of the skull only, as seen in the 

 skull of a Sandwich Islander.' 



In a second skull of a Sandwich Islandet- (No. 695) the frontal 

 grooves are absent, but a number of foramina perforating the outer 

 plate of the bone are directed upward. It would appear that diploic 

 veins had passed into the frontal veins, which had in their turu 

 failed to make any impression upon the bone itself 



Many crania show a vertically placed groove, which is more oi 

 less arborescent, and rather shallow as compared to the frontal, 

 lying upon the squamosal, a short distance above the external audi- 

 tory meatus and reaching as far as the upper limit of the bone, or 

 even crossing the paricto-squamosal suture and describing a curve 

 upward and forward over the parietal bone, a short distance below 

 the temporal crest. In a few examples the track originates in the 

 parieto-squaniosal when the squamosa itself is free. 



The grooves are absent on surfaces from which muscles arise, as 

 is seen on the occiput.^ The squamosal groove is an apparent ex- 

 ception to this conclusion. May it be said that the temporal muscle 

 makes but little traction at the region of the groove '? 



The region of the asterion is quite commonly the seat of numerous 

 closely disposed grooves which are deep and sharply defined. It 

 will be observed that in the above examples the grooves are deepest 

 where the skull is thick, as on the convex frontal bone and in the 

 massive region of the asterion, and most shallow when the bone is 

 the thinnest, as over the squamosal ; also that they may communi- 

 cate with the diploic veins, as in the forehead, or even anastomose 

 Avith an intra-cranial vein, as in the parieto-squamosal suture.^ 



1 No. 572. 



^ I have observed :i branched depression of unknown significance above 

 the nucha-mark in the skull of a Hindoo child four years of age. 



^ For good examples of squamosal vessel-grooves see the following : 542, 

 Miami ; 670, Chinese; 741, Mandan ; 1043, Pawnee; 1283, 1051, Hottentot; 

 59, 987, 1283, 28, unnamed. 



