104 TRANSCENDENTAL ANATOMY IN KN(iLANl) 



In Fig. 5 (page 103) is shown an actual vertebra, as 

 Owen conceives it, the " vertebra '' being that of a bird. 



A segment of sternum is included as the "haemal spine" 

 of the vertebra (//.v) ; the vertebral rib is the " pleura- 

 pophysis " (/>/) ; the sternal rib the " haemapophysis " (//) ; 

 the uncinate process of the vertebral rib is known as the 

 "diverging appendage" (a). The whole vertebrate skeleton 

 is composed of a series of vertebrae which show these typical 

 parts. We arrive thus at the conception of an " Archetype " 

 of the vertebrate skeleton, such as is represented in Fig. 6. 



The archetype is only a scheme of what is usually 

 constant in the vertebrate skeleton, and both the number and 

 the arrangement of the bones in any real Vertebrate are 

 subject to variation. " It has been abundantly proved," 

 Owen writes, towards the end of his volume, " that the idea 

 of a natural segment (vertebra) of the endoskeleton does not 

 necessarily involve the presence of a particular number of 

 pieces, or even a determinate and unchangeable arrange- 

 ment of them. The great object of my present labour has 

 been to deduce . . . the relative value and constancy of 

 the different vertebral elements, and to trace the kind and 

 extent of their variations within the limits of a plain and 

 obvious maintenance of a typical character" (p. 146). 



It goes without saying that Owen considered the skull to 

 be formed of vertebrae the vertebral theory of the skull was, 

 in his system, a deduction from the vertebral theory of the 

 skeleton. He recognised four cranial vertebra- ; the arrange- 

 ment of them, and the relation of their constituent bones to 

 the parts of the typical vertebra are shown in the table 

 appearing on page 106. So far as their first three elements 

 are concerned, these vertebra: are practically identical with 

 the vertebra- distinguished in the classical vertebral theory 

 of the skull, as enunciated by Oken. A divergence appears 

 with the determination of the other elements of the vertebra-. 

 The upper and lower jaws are associated with the nasal and 

 frontal vertebra' respectively, not however as limbs of the 

 head, but as constituent elements of these vertebra-. In the 

 >ame way the hyoid apparatus is part and parcel of the 

 paru-tal vertebra, and the pectoral girdle and fore-limbs part 

 of the occipital vertebra. 



