PLATE V 



PHOTOMICROGRAPHS OF SECTIONS OF THE GNATHAL ELEMENTS 

 A section of the postero-supra'gnathal plate. 



A section of the same plate under higher magnification. The nearly straight line along the top 

 represents the cutting edge. 



A section through the "pick" of the infero-gnathal plate. 

 A more highly magnified section from the same plate. 



Figures 1 and 3, X32; 2 and 4, XI 10. 



