THE SKULL OF OSSEOUS FISHES. 125 



veritablement tres singuliere, et que le manque absolu cle cou, et une 

 combinaison des pieces du sternum avec celles de la tete pouvoient 

 seuls rendre possible." {Aniiales da Museum, ix. p. 361.) 



Oken's latest idea of the essential nature of the arms and legs is, 

 that they are no other than ' liberated ribs : ' " Freye Bewegungs- 

 organe konnen nichts anderes als frey gewordene Rippen seyn." 

 (^Lehrbuch der Natur Philosophie, p. 330. 8vo. 1843.) 



Carus (I.), in his ingenious endeavours to gain a view of the primary 

 homologies of the locomotive members, sees in their several joints 

 repetitions of vertebral bodies {tertiar-ioirhel) — vertebrae of the third 

 degree — a result of an ultimate analysis of a skeleton pushed to the 

 extent of the term ' vertebra ' being made to signify little more than 

 vrhat an ordinary anatomist Avould call a ' bone.' 



But these transcendental analyses sublimate all diflFerences, and de- 

 finite knowledge of a part escapes through the unwarrantable exten- 

 sion of the meaning of terms. We have seen, however, that a ver- 

 tebra is a natural group of bones, that it may be recognised as a pri- 

 mary division or segment of the endo-skeleton, and that the parts 

 of that group are definable and recognisable under all their teleolo- 

 gical modifications, their essential relations and characters appearing 

 through every adaptive mask. 



According to the definition of which a vertebra has seemed to me 

 to be susceptible, we recognise the centrum, the upper (neural) arch, 

 the lower (hsemal) arch, and the appendages, diverging or radia- 

 ting from the hagmal arch. The centrum, though the basis, is not less a 

 part of a vertebra, than are the neurapophyses, ha^mapophyses, pleu- 

 rapophyses, &c. ; and each of these parts is a different part fi'om the 

 other : to call all these parts ' vertebrae ' is in effect to deny their dif- 

 ferential and subordinate characters, and to voluntarily abdicate the 

 power of appreciating and expressing them. The terms 'secondary' 

 or ' tertiary vertebra? ' cannot, therefore, be correctly applied to the 

 appendages of that natural segment of the endo-skeleton to which the 

 term ' vertebra ' ought to be restricted. 



So likewise the term ' rib ' may be given to each moiety of the 

 hajmal arch of a vertebra ; although I would restrict it to that part 

 of such arch to which the term ' vertebral rib ' is applied in Com- 

 parative Anatomy and the term ' pars ossea costa) ' in Anthropotomy : 

 but, admitting the wider application of the term ' rib ' to the whole 

 htemal arch, yet the bony diverging and backward projecting appen- 

 dage of such rib or arch is something difierent from the part support- 

 ing it. Arms and legs may be developments of costal appendages, 

 but cannot be ribs themselves liberated : although liberated ribs may 

 perform analogous functions, as in the Serpents and Dragons. 



