138 Cindnuati Society of Natural History. 



of the ventral surface. Two species have been referred to the genus 

 from our region, as given below. 



1. — P. (?) granuliferus Meek, 1872. 



Disc small, apparently circular; rays rather slender and of 

 unknown length ; dorsal surface covered by an integument composed 

 of innumerable minute grains of calcareous matter; ventral side of 

 disc apparently provided in the interradial spaces with minute spines 

 directed outward ; arm pieces regularly alternating, and apparently 

 rectangular at their inner ends and not interlocking along the minute 

 mesial impressed line, wider than long, each excavated at the auterior 

 outer end so as to form a large pore or pore-like depression and 

 divided transversely by a furrow into two parts, the anterior end very 

 short and the posterior longer, marked by a minute pit at its inner end ; 

 about eight or nine pieces in each range of each row, included within 

 the margin of the disc ; outer arm pieces (adambulacral) smaller than 

 those of the inner ranges, and placed, edge upwards, with an oblique 

 outward direction, so as to imbricate toward the extremities of the 

 rays ; each bearing one or more minute articulating spines ; breadth of 

 disc 0.43 inch; breadth of arms at their inner ends 0.10 inch. (Am. 

 Jour, Sci., ser. 3, vol. 4, p. 274.) 



Locality. — Moore's Hill, Indiana. 



2. — P. miamiensis S. A. Miller, 1882. 



Disc four lines in diameter ; rays one inch long, flexuous and 

 tapering to a point; dorsal surface unknown; ventral surface between 

 the rays with the plates so anchylosed that "no special definition of 

 them can be given ;" rays with two series of sub-quadrangular ambu- 

 lacral ossicles alternating with each other at the bottom of the ambu- 

 lacral plates with spines; oral plates five. (Jour. Cin. Soc. Nat. Hist., 

 vol. 5, p. 116.) 



Locality. — Waynesville, O. 



Remarks. —This is a very unsatisfactorily defined species and 

 needs fuller material. 



Genus 2. — T^ENI ASTER Billings, 1858. 



' 1 Body deeply stellate ; no disc or marginal plates; rays long, 

 slender, flexible, and covered with small spines; two rows of large 



