CONTRIBUTIONS TO PALEONTOLOGY. 149 



NUCLEOCRINUS VERNEUILI. 



Pentremites verneuili : Troost. 

 Olivanites verneuili : Troost. 

 El(zacrinus verneuili : Kcemer. 



This species, which is common in Kentucky and in the limestone at 

 the Falls of the Ohio, and likewise in the State of Ohio, appears under 

 considerable varietj^ of form. It has been illustrated by Dr. F. R(emer in 

 his Monograph of the Blastoidea, and by Mr. S. S. Lyon in the Geological 

 Report of Kentucky. 



A single specimen, bearing the general features of this species, though 

 only one-quarter of an inch in length, has been found by Mr. White at 

 Stafford in Genesee county. The base of the specimen is not concave, 

 but protruding; which I attribute to its young state. Farther collections 

 may prove it to be a distinct species; in which case, I propose the name 

 Nudeocrinus conradi. 



The Nudeocrinus angularis of Lyon has the sides flattened above and 

 concave below; the ambulacral fields forming prominent angles which 

 are approximate below, leaving a narrow base. 



GENUS PENTREMITES (Say). 



PENTREMITES LEDA ( n. s.). ^J 



Body ovate, the greatest width below the centre, triangular at the 

 junction with the column : distance from the column to the base 

 of the pseud ambulacral fields less than one -fourth the entire 

 height. Basal plates small, one quadrangular and two pentangular. 

 Radial plates elongate, narrow, deeply forked ; the greatest width 

 of the extremities equal to one-fourth the length of the plate. 

 Interradial plates small, quadrangular or lozenge-shaped, longer 

 above than below the point of greatest diameter. Pseudambulacral 

 fields long, narrow, slightly widening upward and grooved along 

 the centre, composed of a double series of ornamented poral 

 plates; the plates about eighteen to one-fourth of an inch. Summit 

 openings small. 



Surface marked by very fine, equal, threadlike striae, parallel to 

 the margins of the plates. 



Geological formation and locality. In the shales of the Hamilton group : 

 Western New- York. C. A. WmiE, collector. 



