THE STRUCTURE OF THE HUMAN SKULL. 129 



preoccupied by the pterygoid and the palatine, both of which 

 are connected with the basi-sphenoid (at least with the lingulse), 

 while the anterior part of the palatine is also connected, in the 

 adult state, with the presphenoid, by the intermediation of the 

 cornua sphenoidalia. 



Two bones yet remain to be mentioned which come neither 

 into the category of axial bones, nor of superior or inferior arch 

 bones, nor, strictly speaking, of sense-capsule bones. These are 

 the Lachrymal (L) 9 intercalated between the nasal, maxillary, 

 and lateral mass of the ethmoid, and serving to lodge the con- 

 duit which places the orbit and the nasal cavity in communi- 

 cation ; and the Jugal or Malar (Ju), which connects the bones 

 of the orbital chamber with the squamosal element of the tem- 

 poral bone. 



The skull, thus composed, serves as a protection to the organs 

 which are lodged within it, and which are of as great importance 

 in their morphological, as in their physiological, aspect. 



The cerebral hemispheres and cerebellum, with their de- 

 pendent parts, fill the cranial cavity, the lower lateral margin of 

 the posterior cerebral lobes corresponding with the torcular 

 Herophili and the lateral sinuses, on the inner surface of the 

 occipital bone ; or, in other words, with the line of attachment 

 of the tentorium. Certain axial parts of the brain have definite 

 relations to the axial parts of the cranium. Thus, the medulla 

 oblongata lies upon the basi-occipital. The pituitary body 

 rests upon the upper surface of the basi-sphenoid, this bone con- 

 stituting the chief part of the front as well as of the hinder wall 

 of the sella turcica. The chiasma of the optic nerves rests upon 

 the hinder portion of the upper face of the presphenoid, and the 

 peduncles of the olfactory nerves upon the front portion of that 

 face. The termination of the axial parts of the brain in the 

 lamina terminalis of the third ventricle corresponds pretty 

 nearly with the termination of the basi-cranial axis in the ante- 

 rior extremity of the presphenoid. 



Not less important are the relations of many of the cerebral 

 nerves to the lateral elements of the arches of the brain-case. 



The filaments of the olfactory nerves pass out through the 



K 



