222 



NEW YORK STATE MUSEUM 



ium ending acutely, faintly trilobate, and strongly ringed both on 

 the axial and lateral portions; granulose surface. 



Fig. 153 Homalonotus delphinocephalus, % natural size 



Found rarely in the lower Rochester shale at Niagara, but com- 

 mon in the upper shales. Also found at Lockport and elsewhere 



(Hall). 



Genus illaenus Dalman 



[Ety. : tlXahw, to squint] 



(1828. Uchcr die Palaeaden, p. 51) 



Cephalon and pygidium of about the same size, large and convex, 

 smooth, semicircular in outline, with the trilobations faintly or aot 



