VERTEBRAL THEORY OF THE SKULL. 293 



Although, therefore, the developed skull of the higher 

 Vertebrates, in its peculiar form, its very considerable size, 

 and its complex structure, seems to have nothing in 

 common with ordinary vertebrae, yet the old comparative 

 anatomists at the close of the eighteenth century correctly 

 believed that the skull is originally merely a series of 

 modified vertebrae. In 1790, Goethe " picked up out of the 

 sand of the Jews' burying-ground among the downs near 

 Venice, a dismembered skull of a sheep; he at once per- 

 ceived that the face bones (like the three vertebrae of the 

 back of the skull) are also derivable from vertebrae." And, 

 in 1806, Oken (without knowing of Goethe's discovery), at 

 Ilsenstein, on the way to the Brocken, " found a beautifully 

 bleached skull of a hind ; the thought flashed through him, 

 It is a vertebral column ! " 179 



For the last seventy years, this celebrated " Vertebral 

 Theory of the Skull " has interested the most prominent 

 zoologists ; the most important representatives of Compara- 

 tive Anatomy have exercised their ingenuity in attempting 

 to solve this philosophical skull-problem ; and the question 

 has engaged attention in yet wider circles. It was not till 

 1872 that the solution was found, after seven years of 

 labour, by the comparative anatomist, who, both in the 

 wealth of his real empirical knowledge and in the pro- 

 fundity of his philosophic speculations, surpasses all other 

 students of this science. Karl Gegenbaur, in his classic 

 " Researches in the Comparative Anatomy of Vertebrates " 

 (third part), showed that the skull skeleton of the Selachii 

 is the only record which affords definite proof of the verte- 

 bral theory of the skulL Earlier comparative anatomists 

 erred in starting from the developed mammalian skull, and 



