280 A. Boyde: The Development of Enamel Structure in Mammals 



Prisms within prisms in pig enamel seem to be related to the development of a 

 sharp, raised hump in the middle of the cervical side of the depressions, giving rise 

 to another circumscribed plane of abrupt change of crystallite orientation within the 

 prism. 



Acknozvledgements 



I am very grateful to Mr. R. V. Ely and the M. R. Research Trust for the loan 

 of the Hilger and Watts Stereo-comparator with which the photogrammetric meas- 

 urements have been made, and to Professor Dr. phil. habil. J. G. Helmcke for useful 

 advice and discussions. 



References 



Boyde, A.: The structure and development of mammalian enamel. Thesis. University of 

 London 1964. 



— , and A. D. G. Stextart: Scanning electron microscopy of the surface of developing mam- 

 malian dental enamel. Nature (Lond.) 198, 1102 (1963). 



Fearnhead, R. W.: Mineralization of rat enamel. Nature (Lond.) 188, 509 (1960). 



Watson, M. L.: The extracellular nature of enamel in the rat. J. biophys. biochem. Cytol. 7, 

 489 (1960). 



Gcsamtherstellung: Konrad Trlltsch, Gr.iphischer GroRbetrieb, Wiirzburg 



