THE SKULL. 65 



process of the bone ; and upon each side of this is a ragged 

 hole, called the foramen lacerum basis cranii. Upon either 

 side of the foramen magnum are a couple of proiectino- 

 smooth bodies, termed the condyles, which fit into and 

 articulate with the atlas. A little before, but on either side 

 thf e condyles, are two small holes, known as the 

 condyloid foramina, out of which come the lingual nerves. 

 Near to these are two downward projecting knife-shaped 

 pieces of bone, spoken of as the styloid processes {Skel j j) 

 Above the foramen magnum is a high and sharp continuation 

 ol bone, which forms the pole {Skel h), and from which a 

 sharp line, spoken of as the ridge of the occiput, descends 

 upon either side. 



The internal surface presents the upper part of the 

 basilar process, upon which reposes the medulla oblon2;ata 

 and the pons varoH. 



The PETROUS TEMPORAL (a pair) are the hardest bones in the 

 whole body, owing to their closer texture. Upon the ex- 

 terior is a canal, seeming to lead to the interior of the skull 

 Ihis IS the meatus auditorius or opening to the internal ear 

 {^kel. /), and along the bottom of this canal is stretched, 

 during life, a fine membrane. At the anterior portion 

 of Its interior surface is another styloid process for 

 the attachment of muscles; and behind this is a bulbous 

 projection for the mastoid cells of the internal ear ; upon 

 the internal side of this mastoid process, is a small flat sur- 

 face to which the large horn of the os hyoides is attached. 



rhe SPHENOID BONE (single) is not very unhke a bird. 

 We have two wings, a body, and two legs, looking forward, 

 but not a head. It has two surfaces, an external and an 

 internal. External surface. The body is convex, and receives 

 several muscles. To the legs, also, muscles are attached. 

 1 he wings are flat and smooth ; upon them are two fora- 

 mina, the sphenoidal and the pathetic. With regard to 

 the internal surface. Upon the body rests the cruca cereri 

 and pituitary gland, together with the cavernus sinuses ; 

 its wmgs form imperfect foramina for the superior maxillary 

 nerve, the optic nerve, and the third pair of nerves, to- 

 gether with the orbital, the internal maxillary, and the 

 supra orbital arteries. 



The ETHMOID BONE (single) consists of a body, two 



F 



