SKELETON. 



I6 5 



the ophthalmic branch of the fifth nerves. The maxillaris su- 

 perior and mandibularis branches of the fifth nerve leave the 



FIG. 174. Developing bones in the head of Arnphiuma. Cartilage dotted, 

 bone lined. ao, antorbital process ; an, angulare ; d, dentary ; f, frontal ; fa, fora- 

 men ovale ; mx, maxillary ; o, occipital vertebra ; oc, otic capsule ; pa, parietal ; 

 pm, premaxilla; q, quadrate; sq, squamosal ; st, stapes; /, trabecula; //, etc., exits 

 of nerves. 



skull through the alisphenoid bone, either through a common 

 opening or through two separate foramina (f. ovale for the 

 mandibular, f. rotundum for the other). The seventh nerve 



FIG. 175. Diagram of the relations of the bones in the mammalian skull, 

 after Flower. AS, alisphenoid; BH, basihyal ; BO, basioccipital ; BS, basi- 

 sphenoid; CH, ceratohyal ; EH, epihyal ; EO, exoccipital ; F, frontal; ^, jugal ; 

 L, lachrymal ; MD, mandible; MC, Meckel's cartilage; ME, mesethmoid; MX, 

 maxilla; N, nasal; OS, orbitosphenoid ; PA, parietal; PL, palatine; PM, pre- 

 maxilla ; PS, presphenoid ; FT, pterygoid ; S, squamosal ; SH, stylohyoid ; SO, 

 supraoccipital; T, turbinal ; TH, tympanohyal ; THH, thyrohyal; V, vomer ; 

 I- 1 2, exits of the cranial nerves. 



