THE SKELETON 19 



bone and the frontal bones are a pair of broad, 

 short parietal bones. Each frontal bone is 

 relatively large, and may be divided into 

 frontal, nasal, and orbital parts. From the 

 lateral limit of the bone springs a strong 

 zygomatic process to join the like-named process 

 of the temporal. On each side of the base of 

 the cranium, and connected with the basilar 

 portion of the occipital and the sphenoid, is 

 a temporal bone consisting of a posterior part 

 containing the essential organ of hearing, and 

 an anterior part provided with an articular 

 depression for the quadrate bone. A zygomatic 

 process extends forwards to meet the zygomatic 

 process of the frontal. 



The ethmoid bone may be divided into a 

 horizontal and a perpendicular plate. The 

 former corresponds to the cribriform plate of 

 mammals and has an opening on each side for 

 the passage of the olfactory nerve into the 

 nose. The perpendicular plate forms the inter- 

 orbital septum in which is an opening confluent 

 with the single optic foramen. 



2. Facial Bones. — A pair of small rod-shaped 

 maxillae form the skeleton of part of the sides 

 of the face and assist in the formation of the 

 bony palate. The palatine processes of the 



