94 Transactions of the 



farther than the tracing of the process of ossification, which is but a 

 small, and by no means the most important, part of the whole series of 

 developmental phenomena presented by either the sknll or the verte- 

 bral column. But between the years 1836 and 1839 the appearance 

 of three or four remarkable essays, by Reichert, Hallmann, and 

 Eathke inaugurated a new epoch in the history of the Theory of the 

 SkulL 



" Hallmann's work on the Temporal Bone is especially remarkable 

 for the mass of facts which it contains, and for that clearness of 

 insight into the architecture of the skull which enabled him to deter- 

 mine the homologies of some of the most important bones of its upper 

 arch throughout the vertebral series. 



" Eathke showed the singular nature of the primordial cranial 

 axis, and Eeichert pointed out in what way alone the character of its 

 lower arches could be determined. For the first time the student of 

 the morjihology of the skull was provided with a criterion of the 

 truth or falsity of his speculations, and that criterion was shown to be 

 Development." — P. 5. 



From the same treasure-house I extract the foUowing never-to- 

 be-forgotten axioms : — 



" 1. The notochord of the vertebrate embryo ends in that region 

 of the hasis cranii which ultimately lies behind the centre of the 

 basisi)henoid bone. 



" 2. The basis cranii is never segmented. 



" 8. The lamina perpendicularis of the ethmoid has the same mor- 

 phological value as the jiresphenoid. 



" 4. The petrosal has the same morphological value as the mastoid ; 

 if one is not an integral part of the skull, neither is the other. 



" 5. The nasal bones are not neurapophyses. 



" 6. The branchial arches have the same morphological value as 

 the hyoid, and the latter as the mandibular arc. 



" 7. The mandibular arc is primitively attached behind the point of 

 exit from the skull, of the third division of the fifth nerve. 



" 8. The premaxilla is originally totally distinct from the palato- 

 maxillary arcade. 



" 9. The pectoral arch is originally totally distinct from the 

 skull."— P. 53. 



Having endeavoured to give honour to whom honour is due, 

 I will now, with permission, speak of my own researches. 



On the 28th of June, 1860, I read before the Zoological 

 Society, an abstract of my paper on the Osteology of Balmniceps 

 Bex. I was at that time working out the subject gradationally . 

 But whilst this was in hand, my friend Dr. John Harley showed 

 me what Professor Huxley had been doing, and how completely 

 he had broken up the idols of the transcendentalists ; Professor 

 Euj^ert Jones at the same time lent me the Croonian Lecture. 



The commenced work was set aside ; the microscope was brought 



