NINTH LECTURE. 



THE SEGMENTATION OF THE HEAD.i 



PROF. J. S. KINGSLEY. 



(Tufts College.) 



One of the perennial questions is, " How many segments are 

 there in the vertebrate head ? " We have long realized that 

 the body of a vertebrate is made up of segments as clearly 

 marked as those of a grasshopper or crayfish. Is the head 

 similarly constituted ? 



The first one to suggest such a condition was that mystical 

 naturalist, Oken. As he tells the story, he was walking in the 

 Harz Forest in 1806, when he found the blanched skull of a 

 sheep. His remark upon picking it up was, " It is a vertebral 

 column." The next year, when appointed professor extraordi- 

 nary at Jena, he took for his inaugural address the subject, 

 " The significance of the cranial bones," in which he main- 

 tained that the skull was composed of three vertebrae, — the 

 eye, jaw, and ear or tongue vertebras of his nomenclature. 

 Human skulls separated into these three vertebrae may be had 

 in the shops to-day, and looking at one of them we are struck 

 with the genius of Oken's idea. 



Thirteen years later Gothe claimed the discovery as his own, 

 but time has settled the claim in Oken's favor. 



Oken's theory maintained at least a tacit acceptance for 

 many years, and reached its highest expression in the work of 

 Owen. Oken's followers tried to carry it further and to 

 include other structures than the skull. Thus in the trunk- 



1 The complete paper, of which this is a short abstract, will be published else- 

 where at an early date, with full references to the literature, etc. 



