42 ROYAL SOCIETY OF CANADA 



Plate I. 



Figure 1. — Premolar — molar series of teeth of the left side of Hyra- 



codon priscidens, as seen from below, j^atural size. 

 Figure la. — The same teeth; external view. jSTatural size. 



pr., protoeone; d., deuterocone ; ir., tritocone; te., tetartocone. 



