20 Cincinnati Society of Natural Jlislorij. 



.stricG, wliicii l»('C'Oine more mimerons towai'd tlic mariiin by intercal- 

 ation. 



Marginal pieces on the ventral surface, convex, quite as long as 

 Avide, and numbering in different specimens on each side from eleven 

 to twelve; the piece at the junction of the rays is three times as large 

 as any other of the series, sub-circular, and very convex. 



Adambulacral plates more prominent, slightly wider than long, and 

 numbering, on each side, from nine to ten. Ambulacral pieces a little 

 wider than long, not alternating with the adambulacral plates, and 

 each provided wHh a rather sharp ridge across most of its width. 



There are ten oral plates formed by the junction of the adambulacral 

 rows, which in form and size are scarcely distinguishable from the 

 other plates of those series. 



Greatest breadth measuring between the opposite extremities of the 

 ia3S, 0.7 inch ; breadth of rays at their inner ends, .1 inch ; lengtli of 

 same, 0.3 inch ; diameter of madreporiform piece, 0.02 inch. 



This species is related to P. matutinus, Hall, but has propoitionally 

 shorter rays, is smaller, and has four roAvs of pieces on the dorsal side 

 of the rays instead of three. That species has a circle of stellately 

 marked pieces on the dorsal side of the disk, which feature is not 

 present in the species under consideration. The madreporiform body 

 is also different. P. incomptus^ Meek, has proportionally much shorter 

 rays, larger disk, onlj^ three series of pieces on the dorsal side ot the 

 rays, and a much less con\'ex madreporiform piece. 



In the cabinet of the author there is a complete specimen Avith but 

 four rays, which in all other respects is identical Avith the specimens 

 used in the description. 



Named in honor of the discoverer, Mr. J. G, Fine. 



P'oi'mation and locality: in the Utica slate that is exposed near low 

 water mark in the Ohio River, at Cincinnati, O. 



INCERTA SEDES. 



LtriDOLiTKS, n. gen, 



[Ety. — Lepig, a scale; llthnu, a stone.] 



This generic name is propo-ed for the reception of some very pecul- 

 iar fossils, obtained by Mr. II. E. Dickhaut and the author, near Cov- 

 ington, Ky.. on and in the shale immediately surrounding some of the 

 hard clay nodides, Avhich frequently occur in the shales of the loAver 

 part of the Hudson river group. They consist of much flattened, cal- 

 careous bodies, Avliich in their original state must have had. in the typo 



