Owen and Oken 133 



down the main lines of our knowledge of the skull. In 

 two important respects his statements were not merely 

 a codification of existing knowledge, but an important 

 extension of it. He distinguished the different modes 

 in which the jaws may be suspended to the skull, and 

 established for these different kinds of suspensoria the 

 names which have ever since been employed. He 

 proved clearly what had been suggested by Oken, that 

 the region of the ear is a lateral addition to the skull, 

 and he distinguished in it three bones, his names for 

 which have since become the common property of anat- 

 omists. Finally, he made it plain beyond any possible 

 doubt that the skulls of all vertebrates were built upon 

 a common plan. 



Having established the facts, he proceeded to enquire 

 into the theory. There was now a new method for in- 

 vestigating such problems, the method of embryology, 

 which, practically, had not been available to Oken, and 

 of which neither Cuvier nor Owen had made proper use. 

 By putting together the investigations of a number of 

 embryologists, by adding to these himself, and, lastly, 

 by interpreting the facts which his investigations into 

 comparative anatomy had brought to light, he shewed 

 that the vertebral theory could not be maintained. He 

 shewed, by these methods, that, though both skull and 

 vertebral column are segmented, the one and the other, 

 after an early stage, are fashioned on lines so different 

 as to exclude the possibility of regarding the details of 

 each as mere modifications of a common type. " The 

 spinal column and the skull start from the same primi- 

 tive condition, whence they immediately begin to 

 diverge." " It may be true to say that there is a 

 primitive identity of structure between the spinal or 

 vertebral column and the skull ; but it is no more true 



