226 



ELEMENTAR Y ANA TOMY. 



[LESS, 



be considered as the precursor of the axial system, and the 

 parts of such lamellae as foreshadowing the future carti- 

 laginous and bony complexities . which come ultimately to 

 occupy parts of the areas of such lamellae. Such com- 

 plexities are the most complete expression known to us of 

 the axial skeleton, as the membranous lamellae are its most 

 imperfect and undifferentiated form. 



The parts of the axial skeleton may be tabulated as 

 follows : 



Central 



Bodies of verte- 

 brae (or noto- ' 

 chord). 



Epax 



/"Neural spines. 



u. . 



VNeural arches . 



Prozygapophyses. 



Postzygapophyses- 



Metapophyses. 



Anapophyses. 



Hyperapophyses. 



Zygantrum. 



Zygosphene. 



Paraxial . 



Hypaxial 



Trabeculae. 

 Mandible. 



Cornicula and hyoid. 

 Cornua and hyoid. 

 Branchial arches. 



/"Diapophyses upper ribs. 



' jParapophyses lower ribs 

 V and sternum. 



Hypapophyses (either sin- 

 gle or forked, or as de- 

 tached chevron bones). 



Splanchnapophyses 



Ventral boundary of the 

 heart-sac, never ossified 

 or chondrified. 



13. We may now specially consider the anterior end of the 

 axial skeleton, reviewing the structure of man's skull in the 

 light afforded by the study of other animals. 



That division which was made at starting between the 

 skeleton of the face and of the brain-case now appears to 

 have been both true and significant. 



All the face and both jaws are, we have seen, ossifications 

 around the anterior Splanchnapophyses, and are but of small 

 size compared with the same parts as developed even in 

 some members of man's own class (e.g. the Whale). More- 

 over, we have seen that such parts in him are but mere rudi- 

 ments of what may be developed in other animals, as is made 

 manifest in Fishes, with their largely developed branchial 

 skeleton and complex suspensorial apparatus for the jaws. 



