TEETH OF HESPERORNIS. 15 



Fig. 4. Fig. 6. 



Figure 4. — Vertical section of tooth of Hesperornis regalis, Harsh ; (No. 1206). 

 Figure 5. — Horizontal section of same tooth; both enlarged thirty -two diameters. 

 FlGCBE 6. — Tooth of Hesperornis regalis (No. 1206) ; enlarged eight diameters. 

 Figube 7. — Tooth of Mosasaurus princeps, Marsh ; half natural size. 



a. enamel of crown ; b. dentine ; c. pulp cavity in crown ; V root of tooth ; c'. absorbed cavity i 



d. young tooth ; ss. intersection of horizontal and vertical sections. 



