62 THE TONER LECTURES. 



NoTK. — H. Welcker (Wachsthum und Bau des menschlichen Schiidels, 

 1862, Fig. 7, p. 17) divides the sagittal suture into five parts. These divis- 

 ions are the same as I suggest in the text. My attention was called to 

 Welcker's work by Dr. Frank Baker after I had delivered the lecture. In- 

 stead of naming the parts separately, Welcker includes them in the numbers 

 1, 2, 3, 4, and 5. It will be noticed that this writer retains the post-bregmal 

 division, which I have included with some doubt. The reference of 

 Welcker to the entire subject is very brief and is embraced in the follow- 

 ing language : " For more accurate examination of the shape of these su- 

 tures I have illustrated (Plate iii, Fig. 7) five regions, of which Jfo. 1 is on 

 the coronali ; No. -5 borders on the lambdoida, while No. 4, which lies be- 

 tween the straight parts of the parietal foramina, is a trifle smaller than the 

 other divisions." 



Rolleston (British Barrows, 1877, 02.3), probably influenced by the same 

 authority, speaks of the sagittal suture as divided into fifths. The post- 

 obelial is the " posterior fifth " of this writer, and the obelial the " penulti- 

 mate fifth." 



REMARKS ON THE SUTURES OTHER THAN THOSE OF THE 



VERTEX. 



Sutures often indicate the manner in which the bones have grown. 

 As already stated, the comparatively deep serrations in the middle 

 of the sagittal and coronal sutures correspond to the most preco- 

 cious extensions of growth-force in those directions. Premature 

 union of two opposed portions of bone, namely, at the surfaces of 

 greatest acceleration, may lead to a suture at such portions, being 

 raised above the plane of the adjacent surface. The carinated por- 

 tion of the sagittal suture is an illustration of this peculiarity. A 

 group of instructive examples is seen in the sutures between the 

 maxilla aud the bones adjacent; thus the malo-maxiliary at its 

 lower part, where two obtuse processes project, the process pertain- 

 ing to the maxilla being the larger ; the inequality aud even rugosity 

 of the same suture, as it aids in' defining the lower border of the orbit ; 

 the union of the horizontal plates of the maxillae by means of which 

 an upward extension results, aiding in the composition of the nasal 

 septum ; a downward extension of the same in the form* of a thicken- 

 ing and even of an exostosis, which lies upon the roof of the mouth ; 

 and also in the nasal spine, which is formed at the intermaxillary 



