36 Cincinnati Society of Natural History. 



cephalon, and by the prolongation of the pygidium poster- 

 iorly into a long spine. 



In our specimens, the pygidium is merely pointed and not 

 prolonged into a spine. The axial lobe occupies seven-tenths 

 of the length of the pygidium. It is marked by seven or 

 eight distinct annulations. One or two additional but indis- 

 tinct annulations may be present posteriorly, and at the end 

 there is room for several more, but this part usually is smooth. 

 There are five distinctly grooved pleural segments, one seg- 

 ment occasionally indistinctly grooved, with sometimes a trace 

 of a seventh segment, not grooved. There is no broad flat- 

 tened border along the sides of the pygidium. The associated 

 cephalons do not preserve the median part of the anterior 

 border. The condition of preservation of the specimens here 

 described is not sufficient to determine the presence of gran- 

 ules, but no tubercles were noted. The length of the largest 

 pygidium was estimated at 24 mm., with a width of 26 mm. 

 From this the length of the complete trilobite is estimated at 

 67 mm. 



West Union bed, at the bluff northwest of Alartins, in 

 Lewis county, Kentucky. 



36 



