PLATE XVIII. 

 Lichas (Tehataspis) GKANDIS. 



See Plates 17 and 19. 

 Fig. I. Dorsal view of a very large cephalon wanting' the movable cheeks, showing the double spines on 

 the lateral lobes, and the very broad occipital ring, with the clavate processes upon the posterior 

 margin restored in outline. The specimen shows the base of a strong spine situated just within 

 the palpebral furrow, but this is not represented in the drawing. 

 Fig. '_'. Tin- same viewed from behind, showing the elevatiou of the frontal and lateral lobes. 

 Upper Helderberg group. Cayuga, Province of Ontario. 



