94 ZOOTOMY. 



29. A large articular surface {y) on the side wall of 

 the auditory capsule, formed in front by the sphenotic, 

 behind by the pterotic ; it is covered with cartilage in the 

 recent state and gives articulation to the hyomandibular 



(§ 40). 



30. The frontals (fr) united with one another in the 

 middle line into a single large shield-shaped bone which 

 forms the greater part of the roof of the brain-case, articu- 

 lating behind with the supra-occipital in the middle line, 

 and with the sphenotics externally. 



31. The parietals (/), two flat bones, completing the 

 roofing-in of the brain-case, being wedged in, one on either 

 side, between the supra-occipital internally, the sphenotic 

 and pterotic externally, the frontal in front and the epiotic 

 behind. On the dorsal surface of the parietal is a spine-like 

 process, beneath which is a foramen for the exit of the 

 cutaneous branch of the fifth nerve (§ 98). 



32. The alisphenoids {al.s), two small bones, situated 

 in the side walls of the brain-case, and articulating with the 

 prootic behind and below, and the frontal and sphenotic 

 above. 



33. The parasphenoid (pa.s), a long, stout, median 

 bone, forming the greater part of the base of the skull : 

 posteriorly it widens out, underlaps the basi-occipital and 

 articulates with the prootics : both in front and behind it 

 thins out considerably and ends in a jagged edge. 



34. The vomer {vo), a median bone, forming the 

 anterior part of the base of the skull : it ends in front in a 

 strong transversely curved edge, beset with teeth on its 

 lower surface (§ 161), posteriorly it is pointed and under- 

 laps the parasphenoid. 



35. The mesethmoid {m.e), a median bone situated 

 immediately above the vomer : it is truncated in front, and 



