NEW TRILOBITE FROM ARKANSAS. 59I 



is not depressed or nearly flat, but convex. Secondly, 

 the ornamentation of the axis is entirely different, so 

 much so that it would not warrant its reference to the 

 Illinois species. 



It is doubtful in our present state of knowledge whether 

 Phillipsia ( Griffithides) scitula M. & W. should not be 

 referred to the older name of Phillipsia Cliftonensis Shu- 

 mard, from the Upper Coal Measures, Clifton Park, 

 Kansas, described from a pygidium. Dr. Shumard says 

 that the axis has from 13 to 14 subgranulose rings and 

 seven side segments. A thorough study of all these allied 

 species may necessitate their reference to the older name; 

 but for the present it would be advisable to give the 

 Arkansas species a new name on account of the orna- 

 mentation of its tail. 



